Image Interpreter

Image Interpreter O N - L I N E

M A N U A L

Copyright  1982 - 1999 by ERDAS, Inc. All rights reserved. Printed in the United States of America. ERDAS Proprietary - Delivered under license agreement. Copying and disclosure prohibited without express written permission from ERDAS, Inc. ERDAS, Inc. 2801 Buford Highway, N.E. Atlanta, Georgia 30329-2137 USA Phone: 404/248-9000 Fax: 404/248-9400 User Support: 404/248-9777

Warning All information in this document, as well as the software to which it pertains, is proprietary material of ERDAS, Inc., and is subject to an ERDAS license and non-disclosure agreement. Neither the software nor the documentation may be reproduced in any manner without the prior written permission of ERDAS, Inc. Specifications are subject to change without notice.

Trademarks ERDAS is a trade name of ERDAS, Inc. ERDAS and ERDAS IMAGINE are registered trademarks of ERDAS, Inc. Model Maker, CellArray, ERDAS Field Guide, and ERDAS Tour Guides are trademarks of ERDAS, Inc. Other brands and product names are trademarks of their respective owners.

Image Interpreter On-Line Manual Image Interpreter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Spatial Enhancement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Convolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Non-directional Edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Focal Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Texture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Wallis Adaptive Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Statistical Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Resolution Merge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Crisp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Radiometric Enhance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 LUT Stretch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Histogram Equalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Histogram Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Brightness Inversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Haze Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Noise Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Destripe TM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

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Image Interpreter On-Line Manual Spectral Enhancement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Principal Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Inverse Principal Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Decorrelation Stretch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Tasseled Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Tasseled Cap Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 RGB to IHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 IHS to RGB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Indices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Natural Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Fourier Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Fourier Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Fourier Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Editing Fourier Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Open FFT Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Save Layer As ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Inverse Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Filter Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

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Image Interpreter On-Line Manual Low/High Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Circular Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Rectangular Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Wedge Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Inverse Fourier Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Fourier Magnitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Periodic Noise Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

84

Homomorphic Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Topo Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Surface Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Surface Aspect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Topographic Level Slice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Shaded Relief . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Lambertian Reflection Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Raster Contour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 3D Surfacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Read Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

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Image Interpreter On-Line Manual Save As . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Add Empty Rows To Point List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 Surfacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 GIS Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Neighborhood Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Clump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Sieve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 Eliminate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Perimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 Search . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 Overlay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Recode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Thematic Recode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

Summary By Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

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Image Interpreter On-Line Manual Create Summary Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Summary Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Zonal Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Save Zonal Statistics as Raster Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 Save Zonal Statistics To Polygon Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Change Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Single Input Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Function List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

Two Input Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 RGB Clustering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 RGB Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Layer Selection and Stacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Subset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Create File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Rescale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 Image Degradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

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Image Interpreter On-Line Manual Replace Bad Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 Vector to Raster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

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Image Interpreter

Image Interpreter This menu provides access to the ERDAS IMAGINE Image Interpreter functions. It is opened

when you click on the

icon in the ERDAS IMAGINE icon panel.

Spatial Enhancement ... Click to access functions for enhancing images using the values of individual and surrounding pixels. The Spatial Enhancement menu is displayed.

Radiometric Enhancement ... Click to access functions for enhancing images using the values of individual pixels within each band. The Radiometric Enhancement menu is displayed.

Spectral Enhancement ... Click to access functions for enhancing images by transforming the values of each pixel on a multiband basis. The Spectral Enhancement menu is displayed. HyperSpectral Tools... Click to access functions applicable to hyperspectral data. The HyperSpectral Tools menu is displayed. Fourier Analysis ... Click to access functions for enhancing images using Fourier transformations. The Fourier Analysis menu is displayed.

Topographic Analysis ... Click to access functions applicable to elevation data. The Topo Analysis menu is displayed. GIS Analysis ... Click to access functions for use on thematic data layers. The GIS Analysis menu is displayed.

Utilities ... Click to access some common utilities used on raster layers. The Utilities menu is displayed Close Click to close this dialog. Help Click to see this On-Line Help document.

1

Image Interpreter

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When a continuous file is changed to thematic in ImageInfo, statistics are recalculated using a skip factor of 1 so that all data values present in the file are accounted for. The Skip Factor is shown in the ImageInfo dialog as Skip Factor X and Skip Factor Y. Previous versions of ERDAS IMAGINE allowed files to be changed to thematic without statistics being recalculated. These files may cause problems in some Image Interpreter functions such as Matrix and Summary. If you have files such as this, you may need to manually recompute statistics using ImageInfo before using these files as input to Matrix or Summary.

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

2

Spatial Enhancement

Spatial Enhancement This menu provides access to the Image Interpreter Spatial Enhancement functions. It is opened when you select Spatial Enhancement... from the Image Interpreter menu.

Convolution ... Click to perform convolution filtering on an input image. The Convolution dialog is opened.

Non-directional Edge ... Click to use the Sobel and Prewitt edge enhancement filters. The Non-directional Edge dialog is opened.

Focal Analysis ... Click to perform filtering functions commonly used on thematic data layers. The Focal Analysis dialog is opened. Texture ... Click to perform texture analysis on an input image. The Texture dialog is opened.

Adaptive Filter ... Click to enhance imagery using a filter that adapts to the area within the moving window. The Wallis Adaptive Filter dialog is opened.

Statistical Filter ... Click to enhance an image using a statistical filter. The Statistical Filter dialog is opened.

Resolution Merge ... Click to merge high and low resolution imagery. The Resolution Merge dialog is opened.

Crisp ... Click to sharpen the overall luminance of an input image. The Crisp dialog is opened.

Close Click to close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

3

Convolution

Convolution This dialog allows you to perform image enhancement operations such as averaging, high-pass, or low-pass filtering. You can either define the convolution kernel or you can choose one from the built-in kernel library. You may also select a subset of the input area to process. Each data file value of the new output file is calculated by centering the kernel over a pixel, and multiplying the original values of the center pixel and the appropriate surrounding pixels by the corresponding coefficients from the matrix. So that the output values are within the general range of the input values, these numbers are summed and then divided by the sum of the coefficients. If the sum of the coefficients is zero, this division is not performed. To open this dialog, select Convolution... from the Spatial Enhancement menu.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The default file extension is .img.

Kernel Selection This group lets you define the kernel to be used for convolving the input file. Kernel Library: Enter or select the kernel library. Any kernel you create can be saved to the selected library. The default file extension is .klb. Kernel: This scrolling list shows the kernels contained in the selected library. Select the kernel to be used for this convolution process. Handle Edges By: Sometimes, you may define a kernel size which extends beyond the edges of the image. This option lets you tell IMAGINE what values to use for the area of the kernel which is outside of the image. Reflection Click to fill in the area beyond the edge of the image with a reflection of the values at the edge. For example, if you needed three more rows of data to fill out a kernel, IMAGINE would use the three rows of data nearest the edge in a mirror reflection fashion. Fill

Click to use zeros to fill in the kernel area beyond the edge of the image.

Normalize the Kernel Click to normalize the kernel. Normalizing sums the values of the kernel cells and divides by the number of cells so that the outcome of the weighted average is in the same range as the original pixels. Edit ... Click this button to edit an existing kernel. The kernel editor will display which lets you make changes.

4

Convolution New ...

Click to create a new kernel. The kernel editor is opened.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if these data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click this popup list button to select the data type for the output file.

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

Subset Definition: Use this group to define a rectangular area of the data to use as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

OK Click to run this program with the options selected and close this dialog.

5

Convolution

Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on convolution filtering, see the “Enhancement” chapter in the ERDAS Field Guide.

6

Non-directional Edge

Non-directional Edge This dialog enables you to use the Sobel and Prewitt filters for edge detection. These are two very common filters which use orthogonal kernels convolved separately with the original image, and then combined. This dialog is opened when you select Image Interpreter | Spatial Enhancement... | Nondirectional Edge....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

7

Non-directional Edge LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. Input:

Shows the input file data type.

Output:

Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Filter Selection: Sobel

Select the type of filter to use for this process.

Click to use the Sobel filter:

horizontal:

-1 -2 -1 0 0 0 1 2 1 Prewitt

vertical:

0 -1 0 -2 0 -1

1 2 1

Click to use the Prewitt filter:

horizontal:

-1 -1 -1 0 0 0 1 1 1

vertical:

1 1 1

0 0 0

-1 -1 -1

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog.

8

Non-directional Edge

View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

9

Focal Analysis

Focal Analysis This dialog allows you to perform one of several analyses on data values in an .img file, using a process similar to convolution filtering. To open this dialog, select Image Interpreter | Spatial Enhancement... | Focal Analysis....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate

10

Focal Analysis UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Focal Definition: The check boxes in this kernel let you define the area of the moving window to use for processing. Turn on a check box to include the data value in the computation. Turn off any check boxes representing values you want to exclude from the computation. By turning selected check boxes off, you can create circular and doughnut-shaped kernels. By default, all values are initially turned on (dark). Size:

Click the popup list button to select the kernel size. The choices are:

3x3 5x5 7x7 include This check box is disabled. It only shows that black (selected) check boxes indicate data values that are included in the computation. exclude This check box is disabled. It only shows that gray (unselected) check boxes indicate data values that are excluded from the computation.

Function Definition: This group lets you select options for the output file. Function: function. Sum

Click the popup list button to select the type of computation to use for this The center pixel will be replaced by the sum (total) of the pixels in the window.

Mean The center pixel will be replaced by the mean (average) of the pixels in the window. SD The center pixel will be replaced by the standard deviation of the pixels in the window. Median

The center pixel will be replaced by the median of the pixels in the window.

Max The center pixel will be replaced by the maximum value represented by the pixels in the window.

11

Focal Analysis Min The center pixel will be replaced by the minimum value represented by the pixels in the window. (Use popup list) Click the popup list button to select which values of the input file to use in computing the focal function. Use all values in computation computations. Ignore specified values(s): used to ignore zero. Use only specified value(s): the function.

All values in the input file will be used in the

Ignore the value specified below. This option is often Use only the values specified below when computing

(value) If you want to ignore a certain value, or use only selected values, enter the value(s) here. Enter multiple values as a comma separated list. Enter a range of values using a colon. For example, if you entered 1:5 the computations would use only the values 1, 2, 3, 4, and 5. (Apply popup list) Click the popup list button to select which values of the input file you would like to apply the focal function. Apply function at all values

Apply the function to all values.

Don’t apply at specified values(s): Apply the function to all values except one. This option is often used to ignore zero. Apply only at specified value(s): Apply the function to only the values specified below. For example, you may want to apply a focal function to only certain classes of a thematic file. Using this option, you can enter those classes. (value) If you want to ignore a certain value, or apply the function to only selected values, enter the value(s) here. Enter multiple values as a comma separated list. Enter a range of values using a colon. For example, entering 1:5 would apply the function only to the values 1, 2, 3, 4, and 5. Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. 12

Focal Analysis You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information, see the “Enhancement” chapter in the ERDAS Field Guide.

13

Texture

Texture This dialog lets you apply operators which enhance the texture in a radar or other continuous raster layer. To open this dialog, select Image Interpreter | Spatial Enhancement... | Texture....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. 14

Texture Input:

Shows the input file data type.

Output:

Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Operators: Select the type of computation to use for this process. The algorithms below are discussed in the “Enhancement” chapter of the ERDAS Field Guide. Variance Skewness Window Size:

Use the variance (2nd-order) algorithm. Use the skewness (3rd-order) algorithm. Select the desired window size:

3X3 5X5 7X7

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on texture analysis, see the “Enhancement” chapter in the ERDAS Field Guide.

15

Wallis Adaptive Filter

Wallis Adaptive Filter This dialog provides a filter that “adapts” the contrast stretch to the region of interest (the area within the moving window) using the Wallis Adaptive filter. To open this dialog, select Image Interpreter | Spatial Enhancement... | Adaptive Filter....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. 16

Wallis Adaptive Filter Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Stretch to Unsigned 8 bit Perform a min,max stretch on the input image to the range 0-255.

Moving Window: Select the window size to use. Window Size: Enter the window size to use. Enter only odd numbers. For example, entering a 3 specifies a 3 x 3 window.

Options: Click the popup list button to select options for the output file. Bandwise Click to select the bandwise filtering method. This method filters each band individually. PC Click to select the principal components method of filtering. The first principal component band is filtered, then the inverse principal components is calculated.

Multiplier: Enter the value to use for the multiplier factor to be applied to the scene contrast. The default is 2.0.

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in the Batch Wizard. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

17

Statistical Filter

Statistical Filter This dialog enables you to improve pixel values that fall outside a user-selected statistical range. It is based on the sigma filter used in the Radar module speckle suppression option. In this adaptation, the moving window is set to 5 x 5; large enough to provide meaningful statistics and small enough to minimize blurring. In this filter, the center pixel is replaced by the average of all pixels within the moving window (5 x 5) that fall within a defined range about the center pixel, i.e., DN = [center pixel DN] +/- sigma. Sigma is statistically one standard deviation. Here we assume: sigma = coefficient of variation =

Variance -------------------------Mean

For this filter, sigma is set to 0.15, an average value. This value can be modified by using the multipliers. By using the multipliers, you can increase or decrease the range of values within the moving window used to calculate the average. You may want to use the filter sequentially with increasing multipliers. This will preserve fine detail, yet result in a very smooth final image. To open this dialog, select Image Interpreter | Spatial Enhancement... | Statistical Filter....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file.

18

Statistical Filter From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Multiplier: Click on the appropriate radio button to select the value by which to multiply the input data values. 4.0

Click to multiply input values by 4.

2.0

Click to multiply input values by 2.

1.0

Click to multiply input values by 1.

Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document.

19

Statistical Filter

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

20

Resolution Merge

Resolution Merge This dialog enables you to integrate imagery of different spatial resolutions (pixel size). Since higher resolution imagery is generally single band (for example SPOT Panchromatic 10m data), while multispectral imagery generally has the lower resolutions (for example Landsat TM 30m), these techniques are often used to produce high resolution, multispectral imagery. This improves the interpretability of the data by having high resolution information which is also in color. Resolution Merge offers three techniques: Multiplicative, Principal Components, and Brovey Transform.

♦ Multiplicative is based on simple arithmetic integration of the two raster sets. ♦ The Principal Components merge operates on PC-1 rather than the input raster image. ♦ In the Brovey Transform option, all bands are used according to the following formula: [DNB1 / DNB1 + DNB2 + DNBn ] x [DNhigh res. image ] = DNB1_new [DNB2 / DNB1 + DNB2 + DNBn ] x [DNhigh res. image ] = DNB2_new etc. where B = band This dialog is opened when you select Image Interpreter | Spatial Enhancement... | Resolution Merge....

High Resolution Input File: Enter the name of the high resolution image to use or click on the File Selector button. The default file extension is .img. Select Layer:

Click the popup list button to select the layer to use for the merge.

Multispectral Input File: Enter the name of the multispectral image to use or click on the File Selector button. The default file extension is .img. Number of Layers:

Shows the number of layers in the multispectral image.

Output File: Enter a name for the merged output file or click on the File Selector button. The .img extension will be added automatically.

Method: Click on the appropriate radio button to select the method of computation to use for the merge.

21

Resolution Merge Principal Component This method calculates principal components, remaps the high resolution image into the data range of PC-1 and substitutes it for PC-1, then applies an inverse principal components transformation. The Principal Component method is best used in applications that require the original scene radiometry (color balance) of the input multispectral image to be maintained as closely as possible in the output file. As this method scales the high resolution data set to the same data range as Principal Component 1, before the Inverse Principal Component calculation is applied, the band histograms of the output file closely resemble those of the input multispectral image. Unfortunately, this radiometric accuracy comes at the price of a large computational overhead. The Principal component method is consequently the slower of the three methods offered and requires the most system resources. Another result of this methodology is that the output file tends to have the same data range as the input multispectral file. Consequently it is generally not necessary to use the Stretch to Unsigned 8-bit option for the output file. Instead, simply set the Output Data Type to be the same as the Multispectral Data Type. For instance, if merging an 8-bit SPOT Pan image with an 8-bit Landsat TM image, it would be acceptable to set the Output Data Type to 8-bit. Using this approach minimizes the amount of system resources that would otherwise be used if the Stretch to Unsigned 8-bit option were selected. Multiplicative This method applies a simple multiplicative algorithm which integrates the two raster images. The Multiplicative Method is the simplest of the three methods. As it is computationally simple it is generally the fastest method and requires the least system resources. However, the resulting merged image does not retain the radiometry of the input multispectral image. Instead, the intensity component is increased, making this technique good for highlighting urban features (which tend to be higher reflecting components in an image). Brovey Transform This method uses a ratio algorithm to combine the images as shown above. The Brovey Transform was developed to visually increase contrast in the low and high ends of an images histogram (i.e. to provide contrast in shadows, water and high reflectance areas such as urban features). Consequently, the Brovey Transform should not be used if preserving the original scene radiometry is important. However, it is good for producing RGB images with a higher degree of contrast in the low and high ends of the image histogram and for producing "visually appealing" images.

22

Resolution Merge Since the Brovey Transform is intended to produce RGB images, only three bands at a time should be merged from the input multispectral scene, such as bands 3,2,1 from a SPOT or Landsat TM image or 4,3,2 from a Landsat TM image. The resulting merged image should then be displayed with bands 1,2,3 to RGB.

Resampling Techniques: Click on the appropriate radio button to select the method of resampling for this computation. These resampling techniques are discussed in the “Rectification” chapter of the ERDAS Field Guide. Nearest Neighbor The technique to be used to resample the multispectral input to that of the high resolution image. Bilinear Interpolation The technique to be used to resample the multispectral input to that of the high resolution image. Cubic Convolution The technique to be used to resample the multispectral input to that of the high resolution image.

Output Options: This group lets you select options for the output file. Stretch to Unsigned 8 bit 0 - 255.

Click to stretch the range of data values in the output file to

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file. Using the Stretch to Unsigned 8-bit option causes IMAGINE to perform an extra processing step in which the minimum and maximum DN values produced by the processing so far are calculated to identify the range of values to be rescaled between 0 and 255. It is sometimes useful to do this if the result of a process would otherwise be floating point data or some other data type which consumes more disk space than an Unsigned 8-bit Integer file. However, in order to calculate the minimum and maximum values of the intermediate data, it is generally necessary to create an intermediate file in the Temporary File Directory. Consequently, selecting the Stretch to Unsigned 8-bit option can cause more system resources to be used during processing. This may be avoided by carefully selecting an Output Data Type appropriate to the processing being applied, rather than stretching to Unsigned 8-bit.

Layer Selection: Select the input layers to use. Number of Multispectral Input layers: Shows the number of layers in the multispectral input file.

23

Resolution Merge Select Layers: Enter the layers to input as a comma separated list, for example: 1,3,5. Or enter a range of layers using a colon, for example: 2:5.

Data Type: This group gives information about the input and output file data types. Gray Scale: Multispectral: Output:

Shows the data type of the high resolution input file. Shows the data type of the multispectral input file.

Click the popup list button to select the data type for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

24

Crisp

Crisp This dialog enables you to sharpen the overall scene luminance without distorting the thematic content of the image. To open this dialog, select Image Interpreter | Spatial Enhancement... | Crisp....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

25

Crisp

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output options: This group lets you select options for the output file. Stretch to Unsigned 8 bit 0 - 255.

Click to stretch the range of data values in the output file to

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

26

Radiometric Enhance

Radiometric Enhance This menu provides access to the Image Interpreter Radiometric Enhancement functions. It is opened when you select Radiometric Enhancement... from the Image Interpreter menu.

LUT Stretch ... Left-click to perform a linear contrast stretch. The LUT Stretch dialog is opened.

Histogram Equalization ... Select this option to perform histogram equalization. The Histogram Equalization dialog is opened.

Histogram Match ... Select this option to match the histogram of one image to the histogram of another. The Histogram Match dialog is opened.

Image Inversion ... Select this option to create the reverse or inverse of an image. The Image Inversion dialog is opened.

Haze Reduction ... Select this option to reduce haze in an input image. The Haze Reduction dialog is opened.

Noise Reduction ... Select this option to reduce noise in an input image. The Noise Reduction dialog is opened.

Destripe TM Data ... Select this option to remove striping from a raw TM4 or TM5 data file. The Destripe TM Data dialog is opened.

Close Click to close this dialog. Help Click to read this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

27

LUT Stretch

LUT Stretch This dialog enables you to create an output image that contains the data values as modified by a lookup table. To open this dialog, select Image Interpreter | Radiometric Enhancement... | LUT Stretch....

☞ The input file you select must have a contrast table. You can use the Contrast functions under the Raster option of the Viewer menu bar to create and/or save the contrast table for an image.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

28

LUT Stretch LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Stretch Options: Select the type of lookup table stretch you want to apply to this image. Gray Scale

Click to apply a gray scale stretch to the input file.

Gray: This option displays only if you have selected Gray Scale as your Stretch Option. Enter the input layer to stretch. RGB Click to apply an RGB stretch to the input file. The R, G, and B options below will appear. R:

Select the layer for the red color gun.

G:

Select the layer for the green color gun.

B:

Select the layer for the blue color gun.

Ignore Zero in Output Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document.

29

LUT Stretch

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

30

Histogram Equalization

Histogram Equalization This dialog enables you to apply a nonlinear contrast stretch that redistributes pixel values so that there are approximately the same number of pixels with each value within a range. To open this dialog, select Image Interpreter | Radiometric Enhance... | Histogram Equalization....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

31

Histogram Equalization

Number of Bins: Enter the number of bins into which to divide the values. Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

32

Histogram Matching

Histogram Matching This function mathematically determines a lookup table that will convert the histogram of one image to resemble the histogram of another. To open this dialog, select Image Interpreter | Radiometric Enhance... | Histogram Match....

Input File: Enter the name of the input file or click on the File Selector button. This is the file whose histogram you want to change. The default file extension is .img Band to be Matched: to use.

Click the popup list button to select which band of the input file

Input File to Match: Enter the name of the input file to be matched or click on the File Selector button. The histogram of the first input file will be modified to resemble the histogram of this image as closely as possible. The default file extension is .img. Band to Match to: Click the popup list button to select which band of the match file to use.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension will be added automatically.

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again. 33

Histogram Matching

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. Input #1:

Shows the data type of the first input file.

Input #2:

Shows the data type of the input file to match.

Output:

Click the popup list button to select the data type for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

34

Brightness Inversion

Brightness Inversion This dialog allows both linear and nonlinear reversal of the image intensity range. It produces images which have the opposite contrast of the original image. Dark detail becomes light and light detail becomes dark. To open this dialog, select Image Interpreter | Radiometric Enhancement... | Brightness Inversion....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

35

Brightness Inversion LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Stretch to Unsigned 8 bit. 0 - 255.

Click to stretch the range of data values in the output file to

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file. Reverse Click to create a reverse image of the input file (similar in appearance to a photo negative). The data file values are simply reversed. This can be used to invert a negative image that has been scanned to produce a positive image. Inverse Click to create an inverse image. This function applies an algorithm that emphasizes detail which would otherwise be lost in the darkness of low data file values.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide. 36

Haze Reduction

Haze Reduction This dialog enables you to reduce overall haze in an input image. For multi-spectral images, this method is based on the Tasseled Cap transformation which yields a component that correlates with haze. This component is removed and the image is transformed back into RGB space. For panchromatic images, an inverse point spread convolution is used.

☞ Due to the sensor-specific calculation of the Tasseled Cap transformation, this algorithm should be used only on Landsat 4 TM and Landsat 5 TM imagery This dialog is opened when you left-click Haze Reduction... in the Image Interpreter Radiometric Enhance dialog.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate

37

Haze Reduction UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Method: Click the popup list button to select the type of input image. This popup list is enabled only if the input file you select is a Landsat TM image. Otherwise it defaults to Point Spread. Point Spread This technique can be used for any data type because the kernel used is a model-based generic point spread inversion. Landsat 4 TM The input image is a Landsat 4 Thematic Mapper (TM) scene. Landsat 5 TM The input image is a Landsat 5 Thematic Mapper (TM) scene.

Point Spread Type: Select the type of point spread. This radio button group is enabled only when Point Spread is the selected Method. High

Select this option to use a 5x5 convolution kernel for high-haze conditions.

Low

Select this option to use a 3x3 convolution kernel for low-haze conditions.

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file. OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document.

38

Haze Reduction

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

39

Noise Reduction

Noise Reduction This dialog enables you to reduce the amount of noise in an input raster layer. This technique preserves the subtle details in an image, such as thin lines, while removing noise along edges and in flat areas. It appears when you left-click Noise Reduction... in the Image Interpreter Radiometric Enhance dialog.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

40

Noise Reduction

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

41

Destripe TM

Destripe TM This dialog enables you to destripe TM data. It opens when you select Radiometric Enhancement... | Destripe TM Data... from the Image Interpreter menu.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The default file extension is .img.

Data Type: This group gives information about the input and output file data types. Input:

Shows the input file data type.

Output:

Click this popup list button to select the data type for the output file.

Handle Edges By: Reflection Click to fill in the area beyond the edge of the image with a reflection of the values at the edge. IMAGINE uses the data nearest the edge in a mirror reflection fashion to prevent halo effect on the edges of the output image. Fill Click to use zeros to fill in the area beyond the edge of the image.

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if these data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to use as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer.

42

Destripe TM To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script... from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

43

Spectral Enhancement

Spectral Enhancement This menu provides access to the Image Interpreter Spectral Enhancement functions. It is opened when you select Spectral Enhancement... from the Image Interpreter menu.

Principal Comp. ... Select this option to perform principal components analysis. The Principal Components dialog is opened.

Inverse Principal Comp. ... Select this option to perform inverse principal components analysis. The Inverse Principal Components dialog is opened.

Decorrelation Stretch ... Select this option to maximize the variance in image bands by stretching any number of principal component bands. The Decorrelation Stretch dialog is opened. Tasseled Cap ... Select this option to study vegetation content in an image using the Tasseled Cap transformation. The Tasseled Cap dialog is opened. RGB to IHS ... Select this option to transform an RGB image to IHS. The RGB to IHS dialog is opened.

IHS to RGB ... Select this option to transform an IHS image to RGB. The IHS to RGB dialog is opened.

Indices ... Select this option to calculate vegetation and mineral indices and ratios. The Indices dialog is opened.

Natural Color ... Select this option to simulate natural color from TM data. The Natural Color dialog is opened.

Close Click to close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

44

Principal Components

Principal Components Principal Components Analysis (PCA) is often used as a method of data compression. It allows redundant data to be compacted into fewer bands—that is, the dimensionality of the data is reduced. The bands of PCA data are non-correlated and independent, and are often more interpretable than the source data. PCA can be performed on up to 256 bands with ERDAS IMAGINE. To open this dialog, select Image Interpreter | Spectral Enhancement... | Principal Comp.....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

45

Principal Components LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Stretch to Unsigned 8 bit 0 - 255.

Click to stretch the range of data values in the output file to

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

Eigen Matrix: Specify whether you want to output the eigenmatrix to the Session Log or to a file. Show in Session Log process runs.

Click to write the eigenmatrix to the Session Log when this

Write to file: Click to write the eigenmatrix to a file. This file is necessary if you will be computing an inverse principal components later. Output Text File: Enter the name of the output file or click on the File Selector button. The .mtx extension will be added automatically.

Eigenvalues: Specify whether you want to output the eigenvalues to the Session Log or to a file. Show in Session Log process runs. Write to file:

Click to write the eigenvalues to the Session Log when this

Click to write the eigenvalues to a file.

Output Text File: Enter the name of the output file or click on the File Selector button. The .tbl extension will be added automatically.

Number of Components Desired: Choose the number of output components desired.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file.

46

Principal Components

View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

47

Inverse Principal Components

Inverse Principal Components This dialog enables you to compute an inverse principal components. It is opened when you select Inverse Principal Comp. ... from the Image Interpreter Spectral Enhancement menu.

Input PC File: Enter the input principal component file or click on the File Selector button. This file should have been created using the Principal Components function. The default file extension is .img.

Eigen Matrix File: Enter the input eigenmatrix file or click on the File Selector button. This file is created when the principal components file is created. The default file extension is .mtx.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension will be added automatically.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

48

Inverse Principal Components LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Stretch to Unsigned 8 bit 0 - 255.

Click to stretch the range of data values in the output file to

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

49

Decorrelation Stretch

Decorrelation Stretch This dialog allows you to stretch the principal components of an image, rather than the image itself. It is opened when you left-select Image Interpreter | Spectral Enhancement... | Decorrelation Stretch....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The default file extension is .img.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if these data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to use as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. 50

Decorrelation Stretch Input: Output:

Shows the input file data type. Click this popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Stretch to Unsigned 8 bit 0 - 255.

Click to stretch the range of data values in the output file to

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document.

51

Tasseled Cap

Tasseled Cap This dialog offers a way to optimize data viewing for vegetation studies. The different bands in a multispectral image can be visualized as defining an N-dimensional space where N is the number of bands. Each pixel, positioned according to its data file value in each band, lies within the N-dimensional space. This pixel distribution is determined by the absorption/reflection spectra of the imaged material. To open this dialog, select Image Interpreter | Spectral Enhancement... | Tasseled Cap....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The default file extension is .img.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

52

Tasseled Cap LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Stretch to Unsigned 8 bit 0 - 255.

Click to stretch the range of data values in the output file to

Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

Number of Layers: Shows the number of layers in the input file. Set Coefficients ... Click to enter the coefficients by which to multiply each layer of data values. The Set Coefficients dialog is opened.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

53

Tasseled Cap Coefficients

Tasseled Cap Coefficients This dialog is opened the default coefficients use in this Tasseled Cap computation. You may change the coefficients from this dialog. To open this dialog, click Set Coefficients in the Tasseled Cap dialog.

Coefficient Definition: These number fields show the default coefficients which are used in this Tasseled Cap computation. You may change these values from this dialog.

Output Options: This group lets you select options for the output file. Sensor: type.

Click the popup list button to select the appropriate sensor for the input data

Landsat 4 TM The input data are from the Landsat 4 Thematic Mapper (TM) sensor. Landsat 5 TM The input data are from the Landsat 5 Thematic Mapper (TM) sensor. MSS

The input data are from the Landsat Multispectral Scanner (MSS) sensor.

Number of Layers:

Shows the number of layers in the input data file.

OK Click to run this program with the options selected and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on the Tasseled Cap transformation, see the “Enhancement” chapter in the ERDAS Field Guide.

54

RGB to IHS

RGB to IHS This dialog enables you to apply an algorithm which transforms red, green, and blue values to intensity, hue, and saturation (IHS) values. To open this dialog, select Image Interpreter | Spectral Enhancement... | RGB to IHS....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The default file extension is .img.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

No. of Layers: Shows the number of layers in the input file. 55

RGB to IHS Red: Green: Blue:

Enter the layer to be used for the red value. Enter the layer to be used for the green value. Enter the layer to be used for the blue value.

Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file. OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

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IHS to RGB

IHS to RGB This dialog enables you to transform intensity, hue, and saturation values to red, green, and blue values. To open this dialog, select Image Interpreter | Spectral Enhancement... | IHS to RGB....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

No Stretch Click this radio button to turn off stretching. 57

IHS to RGB

Stretch Intensity Click this radio button to stretch intensity value only to fully utilize the data range.

Stretch Saturation Click this radio button to stretch saturation value only to fully utilize the data range.

Stretch I & S Click this radio button to stretch intensity and saturation values to fully utilize the data ranges.

No. of Layers: Shows the number of layers in the input file. Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

Intensity: Enter the layer to be used as Intensity. Hue: Enter the layer to be used as Hue. Sat: Enter the layer to be used as Saturation. OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Enhancement” chapter in the ERDAS Field Guide.

58

Indices

Indices This dialog provides some commonly used mineral and vegetation ratios and indices. To open this dialog, select Image Interpreter | Spectral Enhancement... | Indices....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Output Options: This group lets you select options for the output file.

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Indices Sensor: Click the popup list button to select the appropriate sensor for the input file data SPOT XS

The input data are SPOT XS (multispectral).

Landsat TM Landsat MSS NOAA AVHRR Radiometer).

The input data are Landsat TM (Thematic Mapper). The input data are Landsat MSS (Multispectral Scanner). The input data are NOAA AVHRR (Advanced Very High Resolution

Stretch to Unsigned 8 bit Left-click to stretch the range of data values in the output file to 0 - 255.

Select Function: Use this scroll list to select the desired index. Different indices are listed depending on the data type. The contents of this list depend upon the sensor that is selected. Function: Shows the formula of the selected function. Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click this popup list button to select the data type for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Natural Color

Natural Color This dialog allows you to simulate natural colors from other types of data. The resulting output image is a fair approximation of the natural colors. To open this dialog, select Image Interpreter | Spectral Enhancement... | Natural Color....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Input band spectral range: Near infrared: Input near infrared band. Red: Red band for IHS calculation. Green: Green band for IHS calculation.

Data Type: This group gives information about the input and output file data types. Input:

Shows the input file data type.

Output:

Click the popup list button to select the data type for the output file.

Stretch Output Range. Stretch output range to 8 bit. Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file.

61

Natural Color From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Fourier Analysis

Fourier Analysis This menu provides access to the Image Interpreter Fourier Analysis functions. Fourier transformation will lead you into the spatial frequency domain. Generally, different objects or different land use/land cover types or noises will show different frequency distributions. You can perform an enhancement (such as low pass or high pass filtering) in this frequency domain, then return to the original spatial domain by using the Inverse Fourier Transform. You can use transform coefficients as new features of your image area or simply keep them, like compressed data, to replace your original image data. This menu is opened when you select Fourier Analysis... from the Image Interpreter main menu.

Fourier Transform ... Left-click to create a Fourier image from a raster layer. The Fourier Transform dialog is opened.

Fourier Transform Editor ... Left-click to edit a Fourier image. The Fourier Editor window will display.

Inverse Fourier Transform ... Left-click to recreate the original raster image from a Fourier image. The Inverse Fourier Transform dialog is opened.

Fourier Magnitude ... Left-click to calculate the magnitude of a Fourier image so that it is visible in an ERDAS IMAGINE Viewer. The Fourier Magnitude dialog is opened.

Periodic Noise Removal ... Left-click to automatically remove striping and other periodic noise from an image. The Periodic Noise Removal dialog is opened. Homomorphic Filter ... Left-click to enhance imagery using a homomorphic filter. The Homomorphic Filter dialog will is opened.

Close Left-click to close this dialog. Help Left-click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on Fourier analysis, see the “Enhancement” chapter in the ERDAS Field Guide.

63

Fourier Transform

Fourier Transform This dialog enables you to create the Fourier transform of a raster layer. To reach this dialog, click on Image Interpreter | Fourier Analysis... | Fourier Transform....

☞ This transform creates a file with a .fft extension. You may view and edit this file with the Fourier Editor tool. You may also process the file using the Fourier Magnitude function to create a .img file which can be displayed in the Viewer.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .fft extension is added automatically. Number of Rows: Shows the number of rows of data in the selected input file. Number of Columns: Shows the number of columns of data in the selected input file. Select Layers: Enter the layers to process as a comma separated list, for example: 1,3,5. Or enter a range of layers using a colon, for example: 2:5.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help file. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information, see the “Enhancement” chapter in the ERDAS Field Guide.

64

Fourier Editor

Fourier Editor This dialog is opened when you select Fourier Transform Editor... from the Fourier Analysis menu of the Image Interpreter. The Fourier Editor allows you to edit Fourier images in order to reduce striping, noise, and other periodic anomalies in raster imagery. Keep in mind that editing Fourier images is an interactive process and there are no set rules for what works best. You will have to experiment with your data and with the different editing tools to find the techniques that work best for you. You can view the coordinates (u ,v ) of the FFT layer by selecting the arrow tool and clicking on or dragging over the .fft layer. The coordinates are reported in the Status Bar at the bottom of the Fourier Editor. The origin (0,0) of an .fft layer is the center.

File Click for options to open .fft files, save edits, close windows, etc. New

Select to create a new Fourier Editor window.

Open...

Select to open a new FFT layer. The Open FFT Layer dialog is opened.

Revert Select to revert to the previously saved version of the file displayed in the Fourier Editor. All edits made in the current session will be undone. Save

Select to save the current .fft layer.

Save All Select to apply the edits made to the currently displayed FFT layer to all layers in the .fft file. This is a convenient way to perform multiband enhancement, since only one FFT layer can be displayed in the Fourier Editor at one time. Save As... Select to save the current FFT layer with a new name. The Save Layer As dialog is opened. Inverse Transform... Select to compute the inverse Fourier transform of the current .fft layer. The Inverse Transform dialog is opened. Clear

Select to remove the current .fft layer from the Editor.

Close

Select to close this Fourier Editor.

Close All

Select to close all open Fourier Editors.

Edit Select to undo edits and specify the filter options to be used with the mouse-driven editing tools on the tool bar.

65

Fourier Editor Undo Select to undo the last operation. Use repeatedly to undo a series of edits, back to the last saved version of the .fft layer. (Select File | Revert to undo all edits made in the current session.) Filter Options... Select to set the filter options to be used by the mouse-driven editing tools on the tool bar. The Filter Options dialog is opened.

Mask The Mask options allows you to perform filtering and masking options on the displayed .fft layer. These options provide the same functionality as the tools on the tool bar. Filters... Select to apply low-pass or high-pass filters. The Low/High Pass Filter dialog is opened. Circular Mask... Select to apply a circular mask to the .fft layer. The Circular Mask dialog is opened. Rectangular Mask... Select to apply a rectangular mask to the .fft layer. The Rectangular Mask dialog is opened. Wedge Mask... Select to apply a wedge mask to the .fft layer. The Wedge Mask dialog is opened.

Help Help for Fourier Editor

Select to see this On-Line Help document.

Click to open a new FFT layer. The Open FFT Layer dialog is opened.

Click to create a new Fourier Editor window.

Click to save the current FFT layer.

Click to remove the current FFT layer from the Editor.

Click to select a Fourier Editing tool from the tool bar. When this tool is selected, you can view the coordinates of any point in the FFT layer. These coordinates are displayed in the Fourier Editor status bar. Click to see a particular coordinate, or drag to dynamically update the coordinate reading.

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Fourier Editor Coordinates are also opened in the status bar while you are using the other mouse-driven editing tools in the tool bar.

Click to use a low-pass filter. In the Fourier Editor, drag from the center to the desired radius. The filter selected in Edit | Filter Options... is the one that is applied. A low-pass filter attenuates the high-frequency components (dark areas) and passes the lowfrequency components (bright areas). This generally has the effect of smoothing or blurring the image. The severity is determined be the radius you choose.

Click to use a high-pass filter. In the Fourier Editor, drag from the center to the desired radius. The filter selected in Edit | Filter Options... is the one that is applied. A high-pass filter attenuates the low-frequency components (bright areas) and passes the high-frequency components (dark areas). This generally has the effect of sharpening or edge-enhancing the image. The severity is determined by the radius you select.

Click to apply a high-pass circular mask that is not centered on the origin. Since FFT images are symmetrical, two circles will be drawn. Drag from the center of the desired circle. The filter selected in Edit | Filter Options... is the one that is applied.

Click to apply a high-pass rectangular mask. Since FFT images are symmetrical, two rectangles will be drawn. Drag one corner to the opposite corner of the desired rectangle. The filter selected in Edit | Filter Options... is the one that is applied.

Click to apply a high-pass wedge mask. The mask extends from the center of the image to the outer edge. Drag from the center of the wedge to enlarge the wedge. The filter selected in Edit | Filter Options... is the one that is applied.

Click to compute the inverse Fourier transform of the current .fft layer. The Inverse Transform dialog is opened.

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

Editing Fourier Images When using the Fourier Editor, you will usually follow these general steps.

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Fourier Editor 1. Create an FFT layer from the image that you want to enhance by selecting the Image Interpreter | Fourier Analysis... | Fourier Transform... option. 2. Open an existing FFT layer (.fft extension) by left-holding File | Open... in the Fourier Editor menu bar or by clicking the open tool on the tool bar. 3. Use the editing tools available from the pull-down menus and/or the editing tools in the Fourier Editor tool bar to edit the FFT layer. All of the options that can be performed with the pull-down menus can also be performed using the mouse-driven tools on the Fourier Editor tool bar. The pull-down menu options allow you to enter precise coordinates, but the mouse tools are more interactive. You can use any combination of these editing options to achieve the desired results. You may want to read the rest of this On-Line Help document before trying these tools, so that you will know how each tool is designed to work. 4. If you are going to use the mouse editing tools, first select Edit | Filter Options... to choose the default filter to use. This is the filter that will be used on all subsequent mouse-driven edits. However, this default filter can be changed at any time. The dialogs that are launched from the pull-down menu options allow you to select a new filter each time that option is selected. 5. If you make an edit, or series of edits, that you do not like, you can undo each edit in reverse sequence by selecting Edit | Undo as many times as desired. You may also select File | Revert to revert back to the last saved version of that FFT layer. 6. After the FFT layer is edited to your satisfaction, save it either under the same name by selecting File | Save or by clicking the save icon on the tool bar. Or, you can save it to a new file by selecting File | Save As.... If the FFT layer that you are editing is one of many in a multiband file, you can apply the same edit(s) to the other layers in the file by selecting the File | Save All option. 7. Now that you have edited and saved the file, you can perform an inverse Fourier transform by selecting File | Inverse Transform.... 8. Display the new file in a Viewer. If your edits were successful, this will be an enhanced version of the original file.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

68

Open FFT Layer

Open FFT Layer This dialog allows you to open an FFT (.fft) layer in the Fourier Editor. The FFT layer must already be created using the Image Interpreter | Fourier Transform... option. This dialog is opened when you select File | Open... from the Fourier Editor menu bar or when you click

on the Fourier Editor tool bar.

FFT Layer: Enter the FFT layer to open, select a directory from the current path, or click on the File Selector button. The default file extension is .fft.

Layer Number: If the selected .fft layer has more than one layer, select the layer to open. OK Click to open this FFT layer and close this dialog. Before the layer is opened in the Fourier Editor, the Fourier Magnitude of the layer is computed. This takes only a few seconds and a progress meter is opened to show you the job status.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

69

Save Layer As ...

Save Layer As ... This dialog enables you to save the current FFT layer as a new file. It appears when you select File | Save As... from the Fourier Editor menu bar.

Save as: Enter a new name for the FFT layer. The default file extension is .fft. OK Click to save the file and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

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Inverse Transform

Inverse Transform This dialog enables you to compute the inverse Fourier transform of the FFT image opened in the Fourier Editor. It is opened when you select File | Inverse Transform... from the menu bar or when you click the

icon on the tool bar of the Fourier Editor.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is added automatically.

Output: Click the popup list button to select the data type for the output file. Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

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Filter Options

Filter Options This dialog allows you to select the default filter that is used with the mouse-driven editing tools on the Fourier Editor tool bar. This dialog is opened when you select Edit | Filter Options... from the Fourier Editor menu bar.

Window Function: Left-hold this popup list to select the default filter that will be used by the mouse-driven editing tools on the Fourier Editor tool bar. This filter will be used in all mouse-driven editing operations until another filter is selected.

➲ The properties of these filters are discussed in detail in the Fourier section of the “Enhancement” chapter in the ERDAS Field Guide. Ideal

Use the Ideal filter.

Bartlett

Use the Bartlett filter.

Butterworth Gaussian Hanning

Use the Butterworth filter.

Use the Gaussian filter. Use the Hanning filter.

Minimum Affected Frequency: Enter the minimum frequency value that will be affected by the filter. Setting this value to a number less than the default of 10.00 might eliminate data that are critical to the content of your image. OK Click to use the selected filter and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

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Low/High Pass Filter

Low/High Pass Filter This dialog allows you to apply a low- or high-pass filter to a circular area. It provides the same functionality as the

and

editing tools on the Fourier Editor tool bar except that control

of parameters is numeric instead of graphic. This dialog is opened when you select Mask | Filters... from the Fourier Editor menu bar.

Filter Type: Click the popup list button to select the type of filter to use. Low Pass Use a low-pass filter. Low frequency components will be passed and highfrequency components will be attenuated. High Pass Use a high-pass filter. High frequency components will be passed lowfrequency components will be attenuated.

Window Function: Left-hold this popup list to select the filter to use. ➲ The properties of these filters are discussed in detail in the Fourier section of the “Enhancement” chapter in the ERDAS Field Guide. Ideal

Use the Ideal filter.

Bartlett

Use the Bartlett filter.

Butterworth Gaussian Hanning

Use the Butterworth filter.

Use the Gaussian filter. Use the Hanning filter.

Radius: Enter the radius (from the center of the image) of the area to filter. If you are using a low-pass filter, the area outside the circle will be filtered. If you are using a high-pass filter, the area inside the circle will be filtered.

Low Frequency Gain: Enter the value by which low-frequency values are multiplied. If the Filter Type selected is Low Pass, then this value defaults to 1.00. If the Filter Type selected is High Pass, then this value defaults to 0.00.

High Frequency Gain: Enter the value by which high-frequency values are multiplied. If the Filter Type selected is Low Pass, then this value defaults to 0.00. If the Filter Type selected is High Pass, then this value defaults to 1.00.

OK Left-click to apply the selected filter and close this dialog.

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Low/High Pass Filter

Cancel Left-click to cancel this process and close this dialog. Help Left-click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

74

Circular Mask

Circular Mask This dialog enables you to use a high pass filtering operation on a circular area that is not centered at the image origin. Since FFT images are symmetrical, two circular areas are filtered. This provides the same functionality as the

tool on the Fourier Editor tool bar except that

control of parameters is numeric instead of graphic. This dialog is opened when you select Mask | Circular Mask... from the Fourier Editor menu bar.

Window Function: Click the popup list button to select the high-pass filter to use. ➲ The properties of these filters are discussed in detail in the Fourier section of the “Enhancement” chapter in the ERDAS Field Guide. Ideal

Use the Ideal filter.

Bartlett

Use the Bartlett filter.

Butterworth Gaussian Hanning

Use the Butterworth filter.

Use the Gaussian filter. Use the Hanning filter.

Circle Center, U: Enter the u (horizontal) coordinate center of the circular areas to be filtered.

Circle Center, V: Enter the v (vertical) coordinate of the center of the circular areas to be filtered.

Circle Radius: Enter the radius of the circular area to be filtered. Central Gain: Enter the value by which to multiply the center of the circle. Entering a number greater than 1.00 increases the values within the radius selected. Entering a number less than 1.00 decreases the values within the radius selected. However, the effect is diminished the farther from the center of the circle you are. For the Ideal filter, all values within the radius are multiplied by the value entered here. For the other filters, the center pixel is multiplied by this value, but the multiplier of the other values is determined by the function of the filter that you are using.

➲ Refer to the Fourier section of the “Enhancement” chapter in the ERDAS Field Guide for the formulas and cross-section illustrations of the available filters.

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Circular Mask

OK Click to apply the selected filter and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using the Fourier Editor, see the ERDAS IMAGINE Tour Guides

76

Rectangular Mask

Rectangular Mask This dialog enables you apply a high-pass mask on a rectangular area. Since FFT images are symmetrical, two rectangular areas are filtered. This provides the same functionality as the tool on the Fourier Editor tool bar except that control of parameters is numeric instead of graphic. This dialog is opened when you select Mask | Rectangular Mask... from the Fourier Editor menu bar.

Window Function: Click the popup list button to select the high-pass filter to use. ➲ The properties of these filters are discussed in detail in the Fourier section of the “Enhancement” chapter of the ERDAS Field Guide. Ideal

Use the Ideal filter.

Bartlett

Use the Bartlett filter.

Butterworth Gaussian Hanning

Use the Butterworth filter.

Use the Gaussian filter. Use the Hanning filter.

UL U: Enter the upper left u coordinate of the rectangular area to filter. LR U: Enter the lower right u coordinate of the rectangular area to filter. UL V: Enter the upper left v coordinate of the rectangular area to filter. LR V: Enter the lower right v coordinate of the rectangular area to filter. Central Gain: Enter the value by which to multiply the center of the rectangle. Entering a number greater than 1.00 increases the values within the rectangular area selected. Entering a number less than 1.00 decreases the values within the rectangular area selected. However, the effect is diminished the farther from the center of the rectangle you are. For the Ideal filter, all values within the rectangle are multiplied by the value entered here. For the other filters, the center pixel is multiplied by this value, but the multiplier of the other values is determined by the function of the filter that you are using.

➲ Refer to the Fourier section of the “Enhancement” chapter of the ERDAS Field Guide for the formulas and cross-section illustrations of the available filters.

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Rectangular Mask

OK Click to apply the selected filter and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

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Wedge Mask

Wedge Mask This dialog enables you to apply a high-pass mask to a wedge-shaped area extending from the origin of the image. Since FFT images are symmetrical, the wedge extends in two directions. This provides the same functionality as the

tool in the Fourier Editor tool bar except that

control of parameters is numeric instead of graphic. This dialog is opened when you select Mask | Wedge Mask... from the Fourier Editor menu bar.

Window Function: Click the popup list button to select the high-pass filter to use. Ideal

Use the Ideal filter.

Bartlett

Use the Bartlett filter.

Butterworth Gaussian Hanning

Use the Butterworth filter.

Use the Gaussian filter. Use the Hanning filter.

Center Angle: Enter the angle at which to place the center of the wedge. 0.00 is a straight horizontal line through the origin. Positive values move the center counterclockwise with a value of 90.00 placing the center of the wedge vertically through the origin. Negative values move the center clockwise from horizontal with a value of -90.00 placing the center of the wedge vertically through the origin.

Fourier image origin

90.00

180.00

0.00

270.00 (-90.00)

Wedge Angle: Enter the angle for the total width of the wedge. The wedge extends outward from the center by half of the degrees entered. For example, if you enter a value of 10.00, the wedge extends 5 degrees from the left of the center and 5 degrees from the right of the center, creating a wedge 10 degrees wide.

Central Gain: Enter the value by which to multiply the center of the wedge.

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Wedge Mask Entering a number greater than 1.00 increases the values within the wedge area selected. Entering a number less than 1.00 decreases the values within the wedge area selected. However, the effect is diminished the farther from the center of the wedge you are. For the Ideal filter, all values within the wedge are multiplied by the value entered here. For the other filters, the center pixel is multiplied by this value, but the multiplier of the other values is determined by the function of the filter that you are using.

➲ Refer to the Fourier section of the “Enhancement” chapter of the ERDAS Field Guide for the formulas and cross-section illustrations of the available filters.

OK Click to apply this filter and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using the Fourier Editor, see the ERDAS IMAGINE Tour Guides

80

Inverse Fourier Transform

Inverse Fourier Transform This dialog enables you to reverse the action of a Fourier Transform. It is opened when you select Inverse Fourier Transform... from the Fourier Analysis menu.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .fft. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is added automatically.

Output: Click the popup list button to select the data type for the output file. Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

81

Fourier Magnitude

Fourier Magnitude This dialog enables you to create an output image from an .fft file which can be displayed in the Viewer. To open this dialog, select Image Interpreter | Fourier Analysis... | Fourier Magnitude....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .fft.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension will be added automatically. Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

82

Periodic Noise Removal

Periodic Noise Removal This dialog enables you to remove periodic noise such as striping from imagery by automatically enhancing the Fourier transform of the image. The input image is first divided into overlapping 128-by-128-pixel blocks. The Fourier Transform of each block is calculated and the logmagnitudes of each FFT block are averaged. The averaging removes all frequency domain quantities except those which are present in each block; i.e., some sort of periodic interference. The average power spectrum is then used as a filter to adjust the FFT of the entire image. When the inverse Fourier Transform is performed, the result is an image which should have any periodic noise eliminated or significantly reduced. This method is partially based on the algorithms outlined in (Cannon, Lehar, and Preston, 1983) and (Srinivasan, Cannon, and White, 1988). If the periodic noise is striping that is due to a sensor problem (i.e. TM4), the Destripe TM tool is the preferred method; if the periodic noise is not sensor related, this is the tool to use. Set the value of the Minimum Affected Frequency as high as possible to achieve the best results. Lower values affect lower frequencies of the Fourier transform which represent global features of the scene such as brightness and contrast. Very high values affect frequencies representing the detail in the image. You can interactively enhance Fourier images using the Fourier Editor. Although the Periodic Noise Removal tool is easier to use than the Fourier Editor, the Fourier Editor may produce better results. This dialog is opened when you select Periodic Noise Removal... from the Fourier Analysis menu of Image Interpreter.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension will be added automatically.

Select Layers: Enter the layers to input as a comma separated list, for example: 1,3,5. Or enter a range of layers using a colon, for example: 2:5.

Minimum Affected Frequency: Enter the minimum spatial frequency value that will be affected by the filter. The range of values is 1 to100.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog.

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Periodic Noise Removal

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides. References Cannon, Michael, Alex Lehar, and Fred Preston, 1983. “Background Pattern Removal by Power Spectral Filtering.” Applied Optics, Vol. 22, No. 6: 777-779. Srinivasan, Ram, Michael Cannon, and James White, 1988. “Landsat Data Destriping Using Power Spectral Filtering.” Optical Engineering, Vol. 27, No. 11: 939-943.

84

Homomorphic Filter

Homomorphic Filter This dialog enables you to enhance imagery using a homomorphic filtering process. This method uses an illumination/reflectance model and is often used to bring out detail in shadowed areas. The pixel values in an image may be thought of as the product illumination and reflectance components. Since illumination tends to change more slowly than reflectance, illumination is associated with the low-frequency components of an image and reflectance with the high frequency parts. To bring out more detail in the image, this function allows you to independently vary the effects of illumination and reflectance in the image.

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If your Pyramid Layers External preference in the Image Files preference category is set to TRUE, the Image Interpreter | Fourier Analysis | Homomorphic Filter produces .rrd files for intermediate image files in the directory specified by the Temporary File Directory preference under User Interface & Session. To recover the disk space, you need to manually remove all files of the form IMAGINE_FFTHMORPH*.rrd and EFFT*.rrd in this directory.

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If your Pyramid Layers External preference in the Image Files preference category is set to TRUE, creation of Fast Fourier Transforms of an image in the same directory as the image by default overwrites the pyramid layers of the original image file. To prevent this, either generate the FFT to a directory different than the image file directory, or change the name of the output FFT from the default. For instance, if you are creating an FFT from myimage.img, name the output myimage_fft.fft rather than the default myimage.fft.

This dialog is opened when you select Homomorphic Filter... from the Image Interpreter Fourier Analysis menu.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Illumination Gain: Enter the value by which to multiply the illumination component of the image. A value between 0 (zero) and 1 decreases the effects of illumination in the output image. A value greater than 1 increases the effects of illumination in the output image.

Reflectance Gain: Enter the value by which to multiply the reflectance component of the image. A value between 0 (zero) and 1 decreases reflectance in the output image. A value greater than 1 increases reflectance in the output image.

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Homomorphic Filter

Cutoff Frequency: Enter the frequency which determines low and high frequencies. Frequencies below this value are considered low frequencies, and above this value are considered high frequencies.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ Refer to the Fourier section of the “Enhancement” chapter in the ERDAS Field Guide for more information.

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Topo Analysis

Topo Analysis This menu provides access to the Image Interpreter Topographic Analysis functions. It appears when you select Topographic Analysis... from the Image Interpreter menu.

Slope ... Select this option to create a percent or degree slope layer from an input elevation layer. The Slope dialog is opened.

Aspect ... Select this option to create an aspect layer from an input elevation layer. The Aspect dialog is opened.

Level Slice ... Select this option to perform a level slice on an input elevation layer. The Level Slice dialog is opened.

Shaded Relief ... Select this option to create a shaded relief layer from an input elevation layer and an optional overlay layer. The Shaded Relief dialog is opened.

Topographic Normalize ... Select this option to reduce the topographic effect in elevation data. The Lambertian Reflection Model dialog is opened.

Raster Contour ... Select this option to create a contour layer from a raster elevation layer. The Raster Contour dialog is opened.

Surface ... Select this option to generate a raster surface from point data. The 3D Surfacing dialog is opened.

Viewshed... Select this option to set up the necessary parameters for performing Viewshed analysis. You must have a DEM in an IMAGINE 2D Viewer to create a Viewshed layer. The Viewshed dialog is opened.

Close Click to close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

87

Surface Slope

Surface Slope This dialog lets you compute the slope of a DEM file. Output can either be in percent or degrees. The input raster file must be georeferenced and you must know whether the elevation data values are in units of feet, meters, etc. Calculations will not work if angular units (x, y; Lat/Lon) are mixed with distance units (z; meters). To open this dialog, select Image Interpreter | Topographic Analysis... | Slope....

Input DEM File: Enter the name of the input elevation file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

88

Surface Slope LR Y: Lower Right Y coordinate

Output Options: This group lets you select options for the output file. Select DEM Layer: operation.

Click the popup list button to select the DEM layer to use for this

Elevation Units: Click the popup list button to select the type of units in which the input data are stored. Centimeters Meters

The input elevation units are meters.

Kilometers Inches Feet

The input elevation units are centimeters.

The input elevation units are kilometers.

The input elevation units are inches. The input elevation units are feet.

Yards

The input elevation units are yards.

Miles

The input elevation units are miles.

Output units: Click on the appropriate radio button to determine the output units. Degree

The output raster layer will contain slope in degrees.

Percent

The output raster layer will contain slope in percent.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. 89

Surface Slope

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about this function, see the “Terrain Analysis” chapter in the ERDAS Field Guide.

90

Surface Aspect

Surface Aspect This dialog lets you compute the aspect of a DEM (digital elevation model) file. To open this dialog, select Image Interpreter | Topographic Analysis... | Aspect....

Input DEM: Enter the name of the input elevation file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

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Surface Aspect

Select DEM Layer: Left-hold this popup list to select the DEM layer to use for this operation.

Output: Left-hold this popup list to select the type of output layer to create. Continuous

Left-hold to create a continuous output layer. This is the default.

Thematic Left-hold to create a thematic output layer. Select this option if you want to recode the output layer.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on topographic analysis, see the “Terrain Analysis” chapter in the ERDAS Field Guide.

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Topographic Level Slice

Topographic Level Slice This dialog allows you to perform a level slice on an input DEM or other raster layer. This function divides the data file values of the input file into a user-specified number of bins that each contain the same number of data values. To open this dialog, select Image Interpreter | Topographic Analysis... | Level Slice....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

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Topographic Level Slice

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Number of Bins: Enter the number of bins into which to divide the input values. Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on topographic analysis, see the “Terrain Analysis” chapter in the ERDAS Field Guide.

94

Shaded Relief

Shaded Relief By knowing the topography of a geographic region and the position of the sun, it is possible to create an image which represents the amount of light reflected to a position directly above the scene. This dialog enables you to produce topographical relief images. The light reflectance is modeled as a simple vector dot product plus an ambient light factor. For each pixel, the change in ground height in the X and Y directions can be computed from a 3 x 3 window centered above the pixel. The two values are used to compute a vector which represents a unit normal to the surface at that point. The dot product of the unit normal and the sun vector gives a value from negative1.0 to 1.0. Values less than zero are clipped to zero. Values of zero represent zero light reflectance and a value of 1.0 represents maximum light reflectance. Calculations will not work if angular units (x, y; Lat/Lon) are mixed with distance units (z; meters). To open this dialog, select Image Interpreter | Topographic Analysis... | Shaded Relief....

Input DEM: Enter the name of the input elevation file or click on the File Selector button. The default file extension is .img.

Select DEM Layer: Click the popup list button to select the DEM layer to use for this operation.

Input Overlay: This file name part is enabled only when you have turned on the Use Overlay in Relief? check box. Enter the name of the .img file to overlay the output relief file or click on the File Selector button. Use Overlay in Relief? Click this check box to overlay an .img file onto the output relief file. The Input Overlay file name part will become enabled. Based on the type of input file the overlay is (gray scale, pseudo color, or true color), you will be asked for the following information.

Overlay Type: If you want to override the default overlay file type, select another option from this popup list. True Color Select this option if the overlay file is a true color image. Assign layers to color guns as described below. R:

Enter the layer to be used for the red color gun in the output file.

G:

Enter the layer to be used for the green color gun in the output file.

B:

Enter the layer to be used for the blue color gun in the output file.

Gray Scale

Select this option if the overlay file is a gray scale image.

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Shaded Relief Layer: If the overlay file is a gray scale image, enter the layer to be used for the overlay. Pseudocolor

Select this option if the overlay file is a pseudocolor image.

Layer: If the overlay file is a pseudocolor image, enter the layer to be used for the overlay.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Ignore Zero in Output Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

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Shaded Relief

Elevation Units: Left-hold this popup list to select the type of units used to measure the elevation. Centimeters Meters

Elevation is measured in meters.

Kilometers Inches Feet

Elevation is measured in centimeters.

Elevation is measured in kilometers.

Elevation is measured in inches. Elevation is measured in feet.

Yards

Elevation is measured in yards.

Miles

Elevation is measured in miles.

DEM scale: Enter the scale to exaggerate the elevation in the DEM for the output file, if desired.

Solar Azimuth: Enter the position of the sun in degrees measured counterclockwise from due east.

Solar Elevation: Enter the sun angle in degrees above the horizon. Ambient Light: Enter the amount of light you want to use for background (overall) lighting. For example, 0 would create a very high contrast image, while 1 would create a washed out (no contrast) image.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about shaded relief images, see the “Terrain Analysis” chapter in the ERDAS Field Guide.

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Lambertian Reflection Model

Lambertian Reflection Model This dialog provides access to a Lambertian reflectance model that can be used to reduce topographic effect in digital imagery. Topographic effect is the difference in illumination due solely to the slope and aspect of terrain relative to the elevation and azimuth of the sun. The net result is an image with more evenly illuminated terrain. You will need to know the solar azimuth and solar elevation of the input file for this function. This information is normally available in the data header of your SPOT or LANDSAT image file. You may use Tools | View IMAGINE HFA File Structure... from the IMAGINE icon panel or if the image is loaded in a Viewer, Utility | HFA Info... from the Viewer menu bar to read the values assigned to sunelevation and sunazimuth. If the data header is not present, you may have to obtain the information from your distributor or it may be retrieved from the original data file using the Tools | View Binary Data... option from the IMAGINE icon panel. Calculations will not work if angular units (x, y; Lat/Lon) are mixed with distance units (z; meters). To open this dialog, select Image Interpreter | Topographic Analysis... | Topographic Normalize....

Input File: Enter the name of the original input file. The default file extension is .img. Input DEM File: Enter the name of the input DEM file from which the slope and aspect will be derived. The default file extension is .img.

Select Layer: Click the popup list button to select the layer of the input DEM file to use. DEM Units: Click the popup list button to select the type of units in which the DEM is stored. Centimeters Meters

Elevation is measured in meters.

Kilometers Inches Feet

Elevation is measured in centimeters.

Elevation is measured in kilometers.

Elevation is measured in inches. Elevation is measured in feet.

Yards

Elevation is measured in yards.

Miles

Elevation is measured in miles.

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Lambertian Reflection Model

Output File: Enter the name of the corrected output file. The .img extension will be added automatically.

Output Options: Enter information about the output file. Solar Azimuth: Enter the solar azimuth of the input file sensor at the time of data acquisition. This information can be obtained from the image file data header or from the distributor. Solar Elevation: Enter the solar elevation of the input file sensor at the time of data acquisition. This information can be obtained from the image file data header or from the distributor. Stretch to Unsigned 8 bit 0 - 255.

Click to stretch the range of data values in the output file to

Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

Data Type: This group gives information about the input and output file data types. Input:

Shows the input file data type.

Input DEM: Output:

Shows the input DEM data type.

Click the popup list button to select the data type for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document.

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Lambertian Reflection Model

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on this function, see the “Terrain Analysis” chapter in the ERDAS Field Guide.

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Raster Contour

Raster Contour This dialog enables you to create a new layer showing contour lines from an input elevation file. This dialog is opened when you select Image Interpreter | Topographic Analysis... | Raster Contour....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

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Raster Contour

Layer to Contour: If the input file has more than one layer, left-hold this popup list to select the one to contour.

Contour Interval: Specify the contour interval. The default value depends on the range of values in the input file. Contour Range: Select the elevation range to contour. The default values are based on the selected contour interval. Min.:

Enter the minimum elevation to contour.

Max.:

Enter the maximum elevation to contour.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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3D Surfacing

3D Surfacing This dialog enables you to create a three dimensional surface from a point data file. It is opened when you select Topographic Analysis | Surface... from the Image Interpreter menu. It can also be opened by selecting Create Surface... from the DataPrep menu.

File Read... Select this option to read data from a file. The Read Points dialog is opened. Save As... Select this option to save the output to a new file. The Save As dialog is opened. Close Click to close the 3D Surfacing tool.

Row Use Only Selected Rows Select this option to set only currently selected rows to Use. Those already set to Use are not set. Add Selected Rows To Used Rows Select this option to add selected rows to those already set to Use. Those already set to Use remain set. Append New Rows To Bottom... Select this option to Add blank rows to end of list. The Add Empty Rows To Point List dialog is opened.

Surface Surfacing... Click to start the surfacing program. The Surfacing dialog is opened.

Help Help for Surfacing Click to open this help file. Show Version...

Click to display software version information.

Click to read data from a file. The Read Points dialog is opened.

Click to save the output to a new file. The Save As dialog is opened.

Click to start the surfacing program. The Surfacing dialog is opened.

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Read Points

Read Points This dialog enables you to read data from an external file. It is opened when you select File | Read... from the 3D Surfacing dialog.

Source File Type: Click the popup list button and select one of the source file types listed below. Point Coverage Line Coverage Annotation Layer Image File ASCII File

When you select this option, the ASCII Import Options dialog is opened.

Source File Name: Enter the source file name or click the File Selector button. The appropriate file name extension is automatically added according to the type of file selected above.

Attribute For Z: This option is displayed only for Vector and Annotation data. Click the popup list button and select the attribute to use for the Z value of each point.

Band: This option is displayed only for Image File data. Enter or select the band number from which Z values are read.

Valid Range for Input: This option is displayed only for Image File data. Enter the maximum and minimum values that are acceptable as Z values. Min: Max:

OK Click to import data as specified. Cancel Click to cancel the operation and close the dialog. Help Click to open this On-Line Help file.

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Save As

Save As This dialog Allows you to save the point data as a Vector point coverage or as an Annotation layer. It is opened when you select File | Save As... from the 3D Surfacing dialog.

Output File Type: Click the popup list button to select the type of file to save the point data to. Point Coverage Annotation Layer

Store data as Point Coverage. Store data as Annotation Layer.

Save Output Coords As: Enter the output file name or click on the File Selector button. The appropriate file name extension for the selected file type is automatically added.

Attribute for Z: Enter the name of attribute in which to store Z value. This option is displayed only when Point Coverage is selected as the Output File Type.

Precision: Click the popup list button to choose to store coverage as single or double precision. This option is displayed only when Point Coverage is selected as the Output File Type. Single Store coverage as single precision. Double Store coverage as double precision.

Store Z value as: Click the popup list button to choose to store Z value in Name or Description. This option is displayed only when Annotation Layer is selected as the Output File Type. Name Store Z value in Name. Description Store Z value in Description.

OK Click to save data as specified. Cancel Click to cancel the operation and close the dialog. Help Click to open this On-Line Help file.

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Add Empty Rows To Point List

Add Empty Rows To Point List This dialog allows you to manually add new rows to the point data. If you want to add rows from another file, use File | Read.... This dialog is opened when you select Row | Append New Rows... from the 3D Surfacing dialog.

Number of Rows To Add: Enter the number of rows you wish to add and click OK. OK Click to add the rows. Cancel Click to cancel the operation and close the dialog.

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Surfacing

Surfacing This dialog enables you to specify information about the output file. It is opened when you select Surface | Surfacing from the 3D Surfacing dialog.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is added automatically.

Surfacing Method: Click the popup list button to select the surfacing technique to employ. Linear Rubber Sheeting Non-linear Rubber Sheeting This option produces more “natural” contours from sparse data.

Output Information: Rows: Enter the number of rows in the output file or accept the default. Columns: Enter the number of columns in the output file or accept the default.

Output Corners: Enter the coordinates of the upper left and lower right corners of the output file or accept the defaults. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Output Cell Sizes: Enter the output file cell sizes or accept the default. X: The Default Output X Cell Size Y: The Default Output Y Cell Size Square Cells Make cell height equal to cell width. With this checkbox selected, a change in one cell size dimension is automatically reflected in the other.

Background Value Enter the background value of output file. This is the value that is used for areas that are outside the realm of the data points.

Ignore In Output Stats When this checkbox is selected, the background value is excluded when computing statistics. 107

Surfacing

Output Data Type: Click the popup list button to select the output data type. OK Click to perform the surfacing operation as specified. A job status dialog is opened to graphically show progress.

Batch Click to place the Surfacing process in a batch queue. Cancel Click to cancel the operation and close the dialog. Help Click to open this On-Line Help file.

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GIS Analysis

GIS Analysis This menu provides access to the Image Interpreter GIS Analysis functions. It is opened when you select GIS Analysis... from the Image Interpreter menu.

Neighborhood ... Select this option to perform neighborhood analyses functions on an input file. The Neighborhood dialog is opened. Clump ... Select this option to identify (clump) contiguous groups of pixels. The Clump dialog is opened.

Sieve ... Select this option to remove (sieve) clumps smaller than a user-specified size. The Sieve dialog is opened.

Eliminate ... Select this option to eliminate small island classes within larger classes. The Eliminate dialog is opened.

Perimeter ... Select this option to find the perimeter of each clump. Use only on a file which is the output of the clump analysis and is writable by the user. The Perimeter dialog is opened.

Search ... Select this option to perform proximity analysis on an input file. The Search dialog is opened. Index ... Select this option to create a composite layer by adding together the pixel values of two input layers. The Index dialog is opened.

Overlay ... Select this option to overlay two input layers based on either the minimum or maximum file values. The Overlay dialog is opened.

Matrix ... Select this option to create a new file that shows the coincidence of values in two input files. The Matrix dialog is opened.

Recode ... Select this option to recode the data file values of an input file. The Recode dialog is opened. Summary ... Select this option to calculate cross-tabulation statistics between to input files and output a report. The Summary dialog is opened.

Zonal Attributes ... Select this option to compute statistics about a raster layer for each polygon in a polygon coverage. The Zonal Attributes dialog is opened.

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If the input raster layer is thematic, make sure that statistics for the layer have been computed with a Skip Factor of 1, otherwise the operation may fail.

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GIS Analysis

Close Click to close this menu. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Neighborhood Functions

Neighborhood Functions This dialog allows you to perform one of several analyses on class values in an .img file using a process similar to convolution filtering. Neighborhood functions are specialized filtering functions that are designed for use on thematic layers. Each pixel is analyzed with the pixels in its neighborhood. The number and location of the pixels in the neighborhood are determined by the size and shape of the filter, which you define. Each filtering function results in the center pixel value being replaced by the result of the filtering function. To open this dialog, select Image Interpreter | GIS Analysis... | Neighborhood....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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Neighborhood Functions

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Neighborhood Definition: The check boxes in this kernel let you define the area of the moving window to use for processing. Turn on a check box to include the data value in the computation. Turn off any check boxes representing values you want to exclude from the computation. By turning selected checkboxes off, you can create circular and doughnut-shaped kernels. By default, all values are initially turned on (black). Size:

Left-hold this popup list to select the kernel size:

3X3 5X5 7X7 include This check box is disabled. It only shows that black (selected) check boxes indicate data values that are included in the computation. exclude This check box is disabled. It only shows that gray (unselected) check boxes indicate data values that are excluded from the computation.

Function Definition: This group lets you select options for the output file. Function:

Select the type of computation to use for this function:

Sum The center pixel will be replaced by the sum (total) of the data file values in the window. Diversity The center pixel will be replaced by the number of different data file values present among the pixels in the window. Density The center pixel will be replaced by the number of pixels in the window with the same data file value as the center pixel.

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Neighborhood Functions Majority The center pixel will be replaced by the most common data file value in the window. Minority The center pixel will be replaced by the least common data file value in the window. Max

The center pixel will be replaced by the highest data file value in the window.

Min

The center pixel will be replaced by the lowest data file value in the window.

Rank The center pixel will be replaced by the rank of the center pixel according to all of the data file values in the window. (Use popup list) Left-hold this popup list to select which values of the input file to use in computing the focal function. Use all values in computation computations. Ignore specified values(s): used to ignore zero. Use only specified value(s): the function.

All values in the input file will be used in the

Ignore the value specified below. This option is often Use only the values specified below when computing

(value) If you want to ignore a certain value, or use only selected values, enter the value(s) here. Enter multiple values as a comma separated list. Ranges of values must also be entered as a comma separated list. (Apply popup list) Left-hold this popup list to select which values of the input file you would like to apply the focal function. Apply function at all values

Apply the function to all values.

Don’t apply at specified values(s): Apply the function to all values except one. This option is often used to ignore zero. Apply only at specified value(s): Apply the function to only the values specified below. For example, you may want to apply a focal function to only certain classes of a thematic file. Using this option, you can enter those classes. (Value) If you want to ignore a certain value, or apply the function to only selected values, enter the value(s) here. Enter multiple values as a comma separated list. Enter a range of values using a colon. For example, entering 1:5 would use apply the function to the values 1, 2, 3, 4, and 5. Ignore Zero in Stats. When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

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Neighborhood Functions

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on neighborhood functions, see the “Geographic Information Systems” chapter in the ERDAS Field Guide.

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Clump

Clump This dialog enables you to identify clumps, which are contiguous groups of pixels in one thematic class. The clumped data are saved in a new .img file which can be used as it is, or as input to the Sieve function. This function also outputs an x,y coordinate for each clump. For more information see the Clump graphical model help. To open this dialog, select Image Interpreter | GIS Analysis... | Clump....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

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Clump LR Y: Lower Right Y coordinate

Select Layer: Click the popup list button to select the layer to use for this operation. Connected Neighbors: Click the popup list button to determine which pixels will be considered contiguous. 8

Left-hold to select eight neighboring pixels as shown in black below.

4

Left-hold to select four neighboring pixels, as shown in black below.

Ignore Zero in Output Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Sieve

Sieve This dialog enables you to eliminate clumps of data values (which have been identified with the Clump function) that are smaller than a minimum size you specify. For more information see the Sieve graphical model help. To open this dialog, select Image Interpreter | GIS Analysis... | Sieve....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

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Sieve

Output Options: This group lets you select options for the output file. Select Layer: Click the popup list button to select the layer to use for processing. Sieve can process only one layer. If a multilayer file is input, the layer to sieve must be selected. Typically, however, the input is a Clump output file, which has one layer. Minimum size: Enter the minimum size to use as the threshold for eliminating clumps. All clumps smaller that this will be filtered. (units popup list) pixels

The minimum size is specified in pixels.

hectares acres sqmiles

Click the popup list button to select the size units.

The minimum size is specified in hectares.

The minimum size is specified in acres. The minimum size is specified in square miles.

Ignore Zero in Output Statistics When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Eliminate

Eliminate The Eliminate function enables you to specify a minimum clump or class size. Clumps smaller than this specified number are eliminated. This function is normally used on thematic raster layers which are the output of the Clump model. Eliminate removes the small clumps by replacing the values of pixels in these clumps with the value of nearby larger clumps. This function makes use of the Eliminate model. The model performs a Focal Majority filter on the input file in an iterative fashion, so that the data value of the large clumps overwrites the data value of the small clumps. With each iteration, the one-pixelwidth outer edge of the small clump is replaced with values from the surrounding larger clumps. The iteration continues until all the small clumps have been completely removed. The final clumps are then recoded using the "Original Value" attribute so that the output values of the remaining clumps are in the same range as the values in the original file which was the input to Clump. Eliminate differs from Sieve in that Sieve simply recodes the small clumps to zero rather than filling in with neighboring values. Also, Sieve does not recode the clumps back to the original "pre-Clump" value.

☞ Before using the Eliminate function, the original raster .img file must first be processed using Clump. This dialog is opened when you select Eliminate... from the Image Interpreter GIS Analysis menu.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file.

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Eliminate From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Select Layer: If the input file contains multiple layers, select the layer to use in this process.

Minimum: Specify the minimum size for the classes or clumps in the file. (units popup list) pixels

The minimum size is specified in pixels.

hectares acres sqmiles

Click the popup list button to select the size units.

The minimum size is specified in hectares.

The minimum size is specified in acres. The minimum size is specified in square miles.

Output: Click the popup list button to select the appropriate output file type. Unsigned 1 bit Unsigned 2 bit Unsigned 4 bit Unsigned 8 bit Unsigned 16 bit Unsigned 32 bit

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Eliminate

Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Perimeter

Perimeter This dialog enables you to compute the perimeter of clumps. It opens when you select Perimeter... from the GIS Analysis dialog. This function cannot execute a read-only file when there is no modal dialog displayed.

Input Clumped File: Enter the input file name. It must be the output of Clump, and must be writable by the user.

Layer: Click on the popup list to select the layer of the input file to clump. Optional Output Descriptors: Island Perimeter Click to make the descriptor for the sum of the perimeter of island polygons. Island Count Click to create a descriptor containing the number of island polygons within each clump.

OK Click to accept all information and issue the job. Batch Click to enter this job as single process batch mode for future processing. Cancel Click to cancel this process and not run the job. Help Click to view the On-Line Help for this dialog.

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Search

Search This dialog enables you to recode the selected classes to 0 in the output file. Neighboring pixels are then assigned a value based on their Euclidean distance from these selected pixels. To open this dialog, select Image Interpreter | GIS Analysis... | Search....

Input Image or Vector: Enter the name of the input image file or vector or click on the File Selector button.

Setup Recode ... Click to recode values for the first input file. The Thematic Recode dialog is opened. This option is displayed only for thematic data.

Vector Type: Click the popup list button to select the type of data to extract from the coverage. These options are displayed only for vector data. Polygon Line Point

Use Attribute As Value: Click this checkbox to use an attribute of the selected coverage type as the input value to the model. This option is displayed only for vector data. When on, this checkbox enables a popup list from which you may select the attribute. If not on, the element number is used as the input value.

Output Image File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

Output Cell Size X and Y cell size to use for rasterizing input vector data into output raster. This option is enabled only when the input file is vector. Units: Select the units for the cell size. This option is enabled only when both input files are vector.

Distance to search (in pixels): Distance from each class value to search. ➲ To search into or shrink a particular class, use one of the following methods:

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Search 1. Search from every class except the class you want to shrink. If the list of class numbers is too large to enter as a comma-separated list in the Search dialog, you may create a simple model using Model Maker and enter the list of classes into a table. Use the GIS Analysis | Neighborhood function. Under Function, select Majority. In the Function Definition options field, set the dropdown list to Ignore specified value(s). This indicates what file values, within the kernel, are used and what are not. Then enter the number for the class to be shrunken in the field directly below it. Also, set the dropdown list next to it to Apply only at specified value(s). This indicates at what file values this focal kernel is used. Again, enter the number for the class to be shrunken in the filed directly below it. For example, to shrink by one pixel around the outside edge, set Size under Neighborhood Definition to 3x3. To shrink by two pixels, select 5x5, and to shrink by three, select 7x7. If you need to shrink by a larger number of pixels, you need to create a simple model using Model Maker. Create a square matrix to use as the neighborhood definition, and make the size of the matrix 2r+1, where r is the number of pixels to shrink.

➲ See Neighborhood Functions for more information on Neighborhood Definition. Classes (enter as a comma separated list): The class value(s) you want proximity analysis around.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below.

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Search UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information, see the “Geographic Information Systems” chapter in the ERDAS Field Guide.

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Index

Index This dialog enables you to create a composite .img file by adding together the class values of two “weighted” input raster files. To open this dialog, select Image Interpreter | GIS Analysis... | Index....

Image or Vector File #1: Select the first input thematic image or vector file or click on the File Selector button. Setup Recode ... Click to recode values for the first input file. The Thematic Recode dialog is opened. This option is displayed only for thematic data. Vector Type: Click the popup list button to select the type of data to extract from the coverage. These options are displayed only for vector data. Polygon Line Point Use Attribute As Value: Click this checkbox to use an attribute of the selected coverage type as the input value to the model. This option is displayed only for vector data. When on, this checkbox enables a popup list from which you may select the attribute. If not on, the element number is used as the input value. Weighting Factor:

Enter the weighting factor for the first input file.

Image or Vector File #2: Select the second input thematic image or vector file or click on the File Selector button. Setup Recode ... Click to recode values for the second input file. The Thematic Recode dialog is opened. This option is displayed only for thematic data. Vector Type: Click the popup list button to select the type of data to extract from the coverage. These options are displayed only for vector data. Polygon Line Point Use Attribute As Value: Click this checkbox to use an attribute of the selected coverage type as the input value to the model. This option is displayed only for vector data. When on, this checkbox enables a popup list from which you may select the attribute.

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Index If not on, the element number is used as the input value. Weighting Factor:

Enter the weighting factor for the second input file.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

Data Type: This group gives information about the input and output file data types. Input #1:

Shows the data type of the first input file.

Input #2:

Shows the data type of the second input file.

Output:

Click the popup list button to select the output file data type.

Output Cell Size X and Y cell size to use for rasterizing input vector data into output raster. This option is enabled only when both input files are vector. Units: Select the units for the cell size. This option is enabled only when both input files are vector.

Area: Use these radio buttons to select how the areas of the input images will be used for the output file. Union

Click to use the combined image area of both input files in this process.

Intersection process.

Click to use only the image area that both files have in common for this

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use.

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Index You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information, see the “Geographic Information Systems” chapter in the ERDAS Field Guide.

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Overlay

Overlay This dialog enables you to create a composite output .img file by combining two input .img files based on the minimum or maximum values of the input files. A recoding option within the Overlay program lets you pre-scale the data, if desired, to “mask out” certain data values. To open this dialog, select Image Interpreter | GIS Analysis... | Overlay....

Image or Vector File #1: Select the first input thematic image or vector file or click on the File Selector button. Setup Recode ... Click to recode values for the first input file. The Thematic Recode dialog is opened. This option is displayed only for thematic data. Vector Type: Click the popup list button to select the type of data to extract from the coverage. These options are displayed only for vector data. Polygon Line Point

Select this option to use polygons for the coverage.

Select this option to use lines for the coverage. Select this option to use points for the coverage.

Use Attribute As Value: Click this checkbox to use an attribute of the selected coverage type as the input value to the model. This option is displayed only for vector data. When on, this checkbox enables a popup list from which you may select the attribute. If not on, the element number is used as the input value.

Image or Vector File #2: Select the second input thematic image or vector file or click on the File Selector button. Setup Recode ... Click to recode values for the second input file. The Thematic Recode dialog is opened. This option is displayed only for thematic data. Vector Type: Click the popup list button to select the type of data to extract from the coverage. These options are displayed only for vector data. Polygon Line Point

Select this option to use polygons for the coverage.

Select this option to use lines for the coverage. Select this option to use points for the coverage.

Use Attribute As Value: Click this checkbox to use an attribute of the selected coverage type as the input value to the model. This option is displayed only for vector data. When on, this checkbox enables a popup list from which you may select the attribute.

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Overlay If not on, the element number is used as the input value.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

Select Area By: Choose one of the following: Union

Click to use the image area of both input files in this process.

Intersection process.

Click to use only the image area that both files have in common for this

Choose Value to Dominate: Left-click on the appropriate radio button to select the value to use for processing: Maximum Value

The output file will contain the maximum value of the input files.

Minimum Value

The output file will contain the minimum value of the input files.

Data Type: This group gives information about the input and output file data types. Input #1:

Shows the data type of the first input file.

Input #2:

Shows the data type of the second input file.

Output:

Click the popup list button to select the output file data type.

Output Cell Size X and Y cell size to use for rasterizing input vector data into output raster. This option is enabled only when both input files are vector. Units: Select the units (meters or feet) for the cell size. This option is enabled only when both input files are vector.

Output: You can set the output to be thematic or continous. OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. 130

Overlay

View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information, see the “Geographic Information Systems” chapter in the ERDAS Field Guide.

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Matrix

Matrix This dialog enables you to create an output file that contains classes that indicate how the class values of the input files overlap. To open this dialog, select Image Interpreter | GIS Analysis... | Matrix....

Thematic Image / Vector #1: Select the first input thematic image or vector file or click on the File Selector button. Setup Recode ... Click to recode values for the first input file. The Thematic Recode dialog is opened. This option is displayed only for thematic data. Vector Type: Click the popup list button to select the type of data to extract from the coverage. These options are displayed only for vector data. Polygon Line Point Use Attribute As Value: Click this checkbox to use an attribute of the selected coverage type as the input value to the model. This option is displayed only for vector data. When on, this checkbox enables a popup list from which you may select the attribute. If not on, the element number is used as the input value.

Thematic Image / Vector #2: Select the second input thematic image or vector file or click on the File Selector button. Setup Recode ... Click to recode values for the second input file. The Thematic Recode dialog is opened. This option is displayed only for thematic data. Vector Type: Click the popup list button to select the type of data to extract from the coverage. These options are displayed only for vector data. Polygon Line Point Use Attribute As Value: Click this checkbox to use an attribute of the selected coverage type as the input value to the model. This option is displayed only for vector data. When on, this checkbox enables a popup list from which you may select the attribute. If not on, the element number is used as the input value.

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Matrix

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

Data Type: This group gives information about the input and output file data types. Input #1:

Shows the data type of the first input file.

Input #2:

Shows the data type of the second input file.

Output:

Click the popup list button to select the output file data type.

Output Cell Size X and Y cell size to use for rasterizing input vector data into output raster. This option is enabled only when both input files are vector. Units: Select the units for the cell size. This option is enabled only when both input files are vector.

Area: Use these radio buttons to select how the areas of the input images will be used for the output file. Union

Click to use the combined image area of both input files in this process.

Intersection process.

Click to use only the image area that both files have in common for this

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document.

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Matrix

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information, see the “Geographic Information Systems” chapter in the ERDAS Field Guide.

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Recode

Recode This dialog allows you to assign a new class value number to any or all classes of an existing .img file, creating an output file using the new class numbers. This function can also be used to combine classes by recoding more than one class to the same new class number. To open this dialog, select Image Interpreter | GIS Analysis ... | Recode ....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Setup Recode ... Click to recode the data values in the input file. The Thematic Recode dialog is opened.

➲ Each time you click Setup Recode ..., the New Value column is reinitialized. If you are recording a large number of rows, you may wish to retain the recoded values so that you can double-check or reedit the New Value column. In this case, it is recommended that you use one of the following techniques:

♦ Use Model Maker to do the recoding. The New Value column is not reinitialized in Model Maker.

♦ Use the Raster Attribute editor to create and edit a column to store the recode values. From the Recode dialog, you can then use the CellArray and Paste options to transfer the recode values to the New Value column.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

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Recode

Cancel Click to cancel this process and close this dialog . View ... Click this button and a Model Maker window will open and display the graphical model used for this function. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information, see the “Geographic Information Systems” chapter in the ERDAS Field Guide.

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Thematic Recode

Thematic Recode The CellArray allows you to recode the raster values or the classes of a raster image. The recoded values are then used in the function definition. All available attributes of the selected raster are opened in this CellArray. The output values of the recode are entered in the New Value column. This dialog is opened when you click on any Setup Recode button.

New Value: Enter the new raster or class value to assign to rows that are selected in the CellArray.

Change Selected Rows Click to apply changes to the table. OK Click to use these values and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Summary

Summary The Summary function produces cross-tabulation statistics that compare class value areas between two thematic files, including number of points in common, number of acres (or hectares or square miles) in common, and percentages. This dialog is opened when you select Summary... from the GIS Analysis menu of Image Interpreter.

Input Zone File: Enter the name of the input zone layer or click on the File Selector button. The default file extension is .img. Layer: If the selected file contains more than one layer, click on the popup list button and select the layer number to use.

Input Class File: Enter the name of the input class layer or click on the File Selector button. The default file extension is .img. Layer: If the selected file contains more than one layer, click on the popup list button and select the layer number to use.

Output Options: Select the type of output desired. Interactive (CellArray)

Click to output the interactive Summary By Zone CellArray.

You can output a report later from the CellArray, if desired. Output Report Only

Click to output a summary report.

Output Report File: If you have selected Output Report Only, you must enter a name for the report or click on the File Selector button. Report Options: Select the options to use when producing the report. These options are enabled when you select Output Report Only. Ignore Zeros

Click to ignore zeros in the class file during statistics calculation.

Omit Empty Classes Click to omit empty classes (with a histogram of 0) from the report. Omit Empty Zones Click to omit empty zones from the report. The report will include only those zones where overlap with the category from the class file actually occurs. This option makes the report shorter.

OK Click to calculate the cross-tabulation statistics and close this dialog. If you selected the Interactive (CellArray) option, the Summary By Zone dialog is opened.

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Summary If you opted to output a report, the report file will be generated.

Batch Click to include this function in a batch file. This option can be used only if you are using the Report option, not when using the Interactive option.

AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual. The two input files do not have to be the same size or the same resolution. The size used for computing statistics is the intersection of the two files. The resolution used is determined by the preference Cellsize Rule in the modeler category of the Preference Editor. This first input file is known as the zone layer. Each class in this layer becomes an analysis category. The system computes statistics for each category based on the occurrences of classes from the second input file, known as the class layer. You can produce an interactive CellArray, a text report, or both. The CellArray option allows you to select options (e.g., Ignore Zeros) to see the effects on the statistics. Then you can choose to create a complete or partial report, or to save the following zonal statistics to the raster attribute table of the zone file. Majority - the most commonly occurring class within a particular zone Mean - the statistical average of the class values in a zone Median - the statistical median of all the classes in a zone Minimum - the minimum class value in a zone Maximum - the maximum class value in a zone Range - the range between the minimum and maximum class values in a zone Diversity - the number of different class values occurring within a zone Standard Deviation - the standard deviation of class values occurring within a zone Majority Count - the number of pixels in the most commonly occurring class in a zone Majority % - the fraction of the total zone which overlaps the majority class

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Summary Example The Summary function might be used to assist a regional planning office in preparing an inventory of landcover types for certain counties within the jurisdiction. A file containing the counties to be inventoried can be summarized by a file for the same geographical area containing the land cover categories. The summary report could indicate the acreage of different land cover types that were contained within the counties.

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Summary By Zone

Summary By Zone Using this CellArray, you can view the summary statistics in a variety of ways, recalculate to ignore zeros or empty classes, view a summary matrix and zonal statistics CellArray, and output a report. This dialog opens when you click OK in the Summary dialog after selecting the Interactive (CellArray) option.

File Select this option to create a report or to close this CellArray. Report... Select this option to create a report file. The Create Summary Report dialog is opened. Close

Select this option to close this CellArray.

Options Select this option for statistics computation options. The information in this CellArray, and in the Summary Matrix and Zonal Statistics CellArrays if they are also open, will change as these options are selected. Ignore Zeros Select this option to ignore zeros in the percentages and statistics. The values in the CellArray will be updated accordingly. Omit Empty Classes Select this option to omit classes with a zero count from the zone listing. Transpose Zones & Classes Select this option to switch the zone layer and class layer. The CellArray information changes accordingly. Area Units Select this option to indicate the area units to use. The column heading in the CellArray changes to reflect the units you select. Hectares Acres

Click to measure area in hectares.

Click to measure area in acres.

Square Miles

Click to measure area in square miles.

View Select this option to view other CellArrays. Summary Matrix Select this option to view a matrix of zones by classes. The Summary Matrix CellArray is opened. Zonal Statistics Select this option to view statistics for the zones. The Zonal Statistics dialog is opened.

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Summary By Zone

Help Click to see this On-Line Help document. Zone layer: The zone layer path and file name is reported. Zone no. The current zone number is reported. Enter a new number or use the slider bar to select another zone.

Zone name: The name of the current zone is reported. Class layer: The class layer path and file name is reported. (CellArray) The CellArray contains the following columns. Right-hold in the Row column for the Row Selection popup. Right-hold on any column heading for the Column Options popup. Class

The class numbers of the class file are listed.

Class Name Count %

The class names of the class file are listed.

The number of pixels in this class that are in the Zone no. listed above is listed.

This value is the percent of the Zone no. listed above covered by this class.

Hectares

This is the area covered by this class in the Zone no. listed above.

This column heading changes according to the units you select in Options | Area Units.

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Create Summary Report

Create Summary Report This dialog enables you to create a report from summary statistics. It opens when you select File | Report... from the Summary By Zone dialog menu bar.

Report All Zones Click to include all zones in the report. This is the default. Start Zone: If you are including only selected zones, enter the first zone number to include here.

End Zone: If you are including only selected zones, enter the last zone number to include here.

Omit Empty Zones Click to omit empty zones from the report. This option will make the report much shorter, especially for files that include many zones.

OK Click to create the report. The report is opened in an ERDAS IMAGINE Text Editor window. Select File | Save As in the Text Editor menu bar to save the report to a file.

Close Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Summary Matrix

Summary Matrix This dialog enables you to view the summary matrix. It opens when you select View | Summary Matrix... in the Summary By Zone dialog.

(CellArray) The summary statistics are presented in a CellArray with the following columns. The information in this CellArray is read-only. Class

The class values of the class file are listed.

Zone Each zone in the zone file is listed in a different column. The number of pixels (Count), area (Area), or percentage of the zone (% of Zone) that each class occupies in that zone is reported. The actual category displayed is selected by left-holding the Show popup list below.

Display Zone & Class Names Click to display both zone and class numbers and names.

Show: Click the popup list button to specify the type of information to report in the CellArray. Count

Select this option to report the number of pixels in each zone.

Area Select this option to report the area each class occupies in each zone. Area units may be selected by left-holding Options/Area Units on the Summary By Zone dialog. % of Zone occupies.

Select this option to report the percentage of each zone that each class

Close Click to close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Zonal Statistics

Zonal Statistics This dialog enables you to view the zonal statistics and save these values to the raster attribute table of the zone file. It opens when you select View | Zonal Statistics... in the Summary By Zone dialog.

(CellArray) The statistics are presented in a CellArray with the following columns. The information in this CellArray is read-only. Zone

The zone numbers of the zone file are listed.

Zone Name Majority Mean

The zone names of the zone file are listed.

The class that occurs most frequently in the zone is listed.

The statistical average of the class values in the zone is listed.

Median

The statistical median of the class values in the zone is listed.

Minimum

The minimum class value found in the zone is listed.

Maximum

The maximum class value in the zone is listed.

Range The range between the minimum and maximum class values in the zone is listed. Diversity

The number of different class values in the zone is listed.

Std. Deviation

The standard deviation of the class values in the zone is listed.

Majority Count The number of pixels in the most commonly occurring class within the zone is reported.

➲ For more information see Rules for Pixel Inclusion within Polygons. Majority % reported.

The fraction of the total zone that is occupied by the majority class is

Close Click to close this dialog. Save... Click to save these statistics to the raster attribute table of the zone file. The Save Zonal Statistics as Raster Attributes dialog is opened. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Save Zonal Statistics as Raster Attributes

Save Zonal Statistics as Raster Attributes This dialog enables you to save the zonal statistics created using the Summary function to the raster attribute table of the zone file. You must select the columns you want to save. This dialog opens when you left-click the Save... button in the Zonal Statistics dialog.

(CellArray) Specify the statistics to include in the raster attribute table by selecting the corresponding rows in this CellArray. Right-hold in the Row column for the Row Selection popup. Right-hold on any column heading for the Column Options popup. The CellArray contains the following columns: Function

The zonal statistics that were calculated are listed.

Attribute Column Name The name that will be used in the raster attribute table is listed. These names can be edited as desired. Overwrite An X in this column indicates that the raster attribute table of the zone file already contains a column with this name and that saving this new column will overwrite the existing column. To avoid overwriting an existing column, simply edit the name in the Attribute Column Name column or left-click in the Overwrite column to automatically generate a new name. New names are created by appending “_NEW” to the existing name.

OK Left-click to save the selected attribute columns to the zone file’s raster attribute table and close this dialog. This button is not enabled until at least one row is selected.

Cancel Left-click to cancel this process and close this dialog. Help Left-click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Save Zonal Statistics To Polygon Attributes

Save Zonal Statistics To Polygon Attributes This dialog enables you to extract the zonal statistics of the background image of a polygon coverage and save them as polygon attributes. To open this dialog, select Image Interpreter | GIS Analysis... | Zonal Attributes... or select Zonal Attributes... from the Vector Utilities menu.

Vector Layer: Enter the name of the input polygon coverage or click on the File Selector button. The default file extension is .arcinfo.

Raster Layer: Enter the name of the input raster file or click on the File Selector button. The default file extension is .img.

Data Type: The data type of the selected input raster file is displayed. Select Layer: Click the popup list button to select the layer of the input raster to use. Window: Union

Select the area of the files to process. Click to use the image area of both input files in this process.

Intersection process.

Click to use only the image area that both files have in common for this

Ignore Zero in Zonal Calculations When this check box is on, the value zero is ignored in the computation of zonal statistics.

Zonal Functions: Majority Include zonal majority among stats Attribute Name: Name for output polygon attribute Max Include zonal max among stats Attribute Name: Name for output polygon attribute Min Include zonal min among stats Attribute Name: Name for output polygon attribute Mean Include zonal mean among stats Attribute Name: Name for output polygon attribute Median Include zonal median among stats

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Save Zonal Statistics To Polygon Attributes Attribute Name: Name for output polygon attribute Diversity Include zonal diversity among stats Attribute Name: Name for output polygon attribute Range Include zonal range among stats Attribute Name: Name for output polygon attribute Standard Deviation Include zonal std. deviation among stats Attribute Name: Name for output polygon attribute Majority Count Include zonal majority count among stats Attribute Name: Name for output polygon attribute Majority Fraction Include zonal majority fraction among stats Attribute Name: Name for output polygon attribute

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information on which pixels are included within the polygons, see the On-Line Help for Rules for Pixel Inclusion within Polygons.

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Utilities

Utilities This menu provides access to the Image Interpreter Utilities. It is opened when you select Utilities... from the Image Interpreter menu.

Change Detection ... Select this option to compute the differences between two images and to highlight changes that exceed a user-specified threshold. The Change Detection dialog is opened. Functions ... Select this option to process an input file using one of many mathematical functions in the Spatial Modeler Language such as SIN, COS, etc. The Single Input Functions dialog is opened. Operators ... Select this option to perform simple image algebra functions on two input images. The Operators dialog is opened.

RGB Clustering ... Select this option to compress three bands of data into one using RGB clustering. The RGB Clustering dialog is opened.

Adv. RGB Clustering ... Select this option to perform RGB clustering on one or more input image files. The RGB Cluster dialog is opened.

Layer Stack ... Select this option to create a new output file by stacking layers from two or more different input images. The Layer Stack dialog is opened.

Subset ... Select this option to create a new file by subsetting an input file. The Subset dialog is opened.

Create File ... Select this option to create a file of specified size, data type, etc. The Create File dialog is opened.

Rescale ... Select this option to rescale data in any bit format. The Rescale dialog is opened.

Mask ... Select this option to use an .img file to select (mask) specific areas from a corresponding .img file. The Mask dialog is opened.

Degrade ... Select this option to reduce the resolution of an image. The Image Degradation dialog is opened. Replace Bad Lines ... Select this option to replace bad scan lines in raster data. The Replace Bad Lines dialog is opened.

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Utilities

Vector To Raster ... Select this option to convert a vector coverage to a raster coverage. The Vector to Raster dialog is opened.

Reproject ... Select this option to resample an image into a different projection. Close Click to close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For step-by-step instructions on using many of the Image Interpreter functions, see the ERDAS IMAGINE Tour Guides.

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Change Detection

Change Detection Select this option to compute the differences between two images and to highlight changes that exceed a user-specified threshold. You will be creating two new output image files, which you can save to a directory. Open a viewer to see the files. To open this dialog, select Image Interpreter | Utilities... | Change Detection....

Before Image: The Before Image is the earlier of the two images. If you are comparing bands of one image, you do not have to click to select from the Before Image dropdown list. Layer: If you are working with a multiband image, you may choose any band for analysis in conjunction with the Before Image. The Before Image should match the After Image when you compare the two images.

After Image: The After Image is subtracted from the Before Image to provide the image difference and Highlight Change image. The After Image is the more recent of your two themes and reflects change over time. Layer: If you are working with a multiband image, you may choose any band for analysis in conjunction with the After Image. The After Image should match the Before Image when you compare the two images.

Image Difference File: A grayscale image composed of single band continuous data. This image is the direct result of subtraction of the Before Image from the After Image. Since Change Detection calculates change in brightness values over time, the Image Difference File reflects that change using the grayscale image. Type in a name for this file here and save it to a directoy.

Highlight Change File: The Highlight Change Image is a five-class thematic image, typically divided into the five categories of Background, Decreased, Some Decreased, Unchanged, Some Increase, and Increased. Type in a name for this file here and save it to a directory. Highlight Changes: As Percent Click the As Percent button to see the changes in brightness as a percent. The As Percent option works well with continuous data images. As Value Click the As Value button to see the changes in brightness as a direct result of subtraction. The As Value option works well with GRID data, like evaluation values. Increases more than: Type a number in the Increases more than text box. After application of Change Detection, increases in brightness values, more than the number you enter, are highlighted in the color you select in the as field.

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Change Detection as This field is a color chooser for your brightness values. Click on the document button next to the field to display a color selection. To further customize your selection, select Other... to display the Color Chooser. For optimim performance, select your color each time you make a new image. Decreases more than: Type a number in the Decreases more than text box. After application of Change Detection, decreases in brightness values, more than the number you enter, are highlighted in the color you select in the as field. as This field is a color chooser for your brightness values. Click on the document button next to the field to display a color selection. To further customize your selection, select Other... to display the Color Chooser. For optimim performance, select your color each time you make a new image.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document.

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Single Input Functions

Single Input Functions This dialog lets you select a Spatial Modeler Language function to use in processing. To open this dialog, select Image Interpreter | Utilities... | Functions....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

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Single Input Functions

Select Function: From this scroll list, select the function you want to apply to the input file. Each function is explained briefly in the Function List below.

Data Type: This group gives information about the input and output file data types. Input:

Shows the input file data type.

Output:

Click the popup list button to select the data type for the output file.

Output Options: This group contains options for the output file. Select Input Layers: function. All

Click the popup list button to select the layers to use for this

Use all layers of the input file.

Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

Function List ABS ACOS

Absolute Value: computes the absolute value of <arg1>. Arccosine: computes the arccosine of <arg1>.

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Single Input Functions ACOSH

Hyperbolic Arccosine: computes the hyperbolic arccosine of <arg1>.

ANGLE

Angle: returns the angle for complex numbers and zero for other types.

ASIN

Arcsine: computes the arcsine of <arg1>.

ASINH

Hyperbolic Arcsine: computes the hyperbolic arcsine of <arg1>.

ATAN

Arctangent: computes the arctangent of <arg1>.

BINARY CEIL

Convert to Binary: returns true if non-zero, false if zero.

Ceiling: computes the least integer greater than or equal to <arg1>.

CONJ Complex Conjugate: returns the conjugate of complex numbers, i.e., real part minus imaginary part. Returns <arg1> for other types. COS

Cosine: computes the cosine of <arg1>. Enter <arg1> in radians.

COSH

Hyperbolic Cosine: computes the hyperbolic cosine of <arg1>.

DELTA

Delta: true if <arg1> is zero, false otherwise.

EVEN EXP

Test if Even: returns true if <arg1> is an even number, false otherwise. Exponential: computes e raised to the <arg1> power.

FLOOR

Floor: computes the greatest integer less than or equal to <arg1>.

GAMMA

Gamma: computes the gamma function of <arg1>.

IMAG Imaginary Part: returns the imaginary part of complex numbers. Returns zero for other types. INV Multiplicative Inverse: computes the multiplicative inverse of <arg1>, i.e., 1. / <arg1>. LOG

Natural Logarithm: computes the natural logarithm of <arg1>.

LOG10 ODD

Common Logarithm: computes the common logarithm (base 10) of <arg1>. Test if Odd: returns true if <arg1> is an odd number, false otherwise.

REAL types.

Real Part: returns the real part of complex numbers. Returns <arg1> for other

RECT

Rectangle: returns: ABS (<arg1>) <= 0.5.

ROUND

Round: computes the nearest integer to <arg1>.

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Single Input Functions SIGN Sign: determines the sign of <arg1>. Returns 1 if <arg1> is positive, 0 if 0, -1 if negative. SIN

Sine: computes the sine of <arg1>. Enter <arg1> in radians.

SINC

Sinc: returns (SIN (π * <arg1>)) / (π * <arg1>).

SINH

Hyperbolic Sine: computes the hyperbolic sine of <arg1>.

SQRT

Square Root: computes the square root of <arg1>.

STEP

Step: returns true if <arg1> >= 0, false otherwise.

TAN

Tangent: computes the tangent of <arg1>. Enter <arg1> in radians.

TANH TRI

Hyperbolic Tangent: computes the hyperbolic tangent of <arg1>.

Triangle: computes MAX (1. - ABS (<arg1>), 0.).

TRUNC

Truncate: truncates <arg1> to integer by removing the fractional part.

WHOLE Test if Whole Number: returns true if <arg1> is a whole number (a nonnegative integer). Returns false otherwise.

➲ See the on-line Spatial Modeler Language manual for more detailed information about each function.

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Two Input Operators

Two Input Operators This dialog lets you perform simple image algebra operations on two input files. To open this dialog, select Image Interpreter | Utilities... | Operators....

Input File #1: Enter the name of the first input file or click on the File Selector button. The default file extension is .img. Layer: Click the popup list button to select the layer to use for this operation. You can select All layers.

Input File #2: Enter the name of the second input file or click on the File Selector button. The default file extension is .img. Layer: Click the popup list button to select the layer to use for this operation. You can select All layers.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Output Options: This group lets you select options to use in creating the output file. Operator:

Click the popup list button to select the operator to use.

+

Addition

-

Subtraction

* /

Multiplication Division

POWER MOD

Raise to Power: raise <arg1> to <arg2> power.

Modulus

Select Area By: options. Union

Determine the processing area by selecting one of the following

Click to use the image area of both input files in this process.

Intersection Click to use only the image area that both files have in common for this process.

Ignore Zero in Output Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

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Two Input Operators

Data Type: This group gives information about the input and output file data types. Input #1:

Shows the data type of the first input file.

Input #2:

Shows the data type of the second input file.

Output:

Click the popup list button to select the output file data type.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information, see the Spatial Modeler Language on-line manual.

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RGB Clustering

RGB Clustering This dialog allows you to perform RGB clustering on an input image file. RGB clustering can be used to compress three bands of data into one, or to perform a simple unsupervised classification. It is often used to rescale 24-bit data to 8-bit data. This dialog is opened when you select Image Interpreter | Utilities... | RGB Clustering....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

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RGB Clustering

No. of Layers: Shows the number of layers in the input file. Red: Green: Blue:

Enter the layer to use as the red value. Enter the layer to use as the green value. Enter the layer to use as the blue value.

Total Bins: Shows the total number of bins into which the input file is currently divided. R Bin: Enter the number of bins to use for the red value. The default of 7 often produces good results. G Bin: Enter the number of bins to use for the green value. The default of 6 often produces good results. B Bin: Enter the number of bins to use for the blue value. The default of 6 often produces good results.

Stretch Method: Click on the appropriate radio button to select the type of contrast stretch to apply to the output file. (This stretch is applied before the binning). Standard Deviation

A standard deviation stretch will be applied to the data.

Min-Max The data will be stretched between the minimum and maximum data file values of each band of the input file. # Std Devs: Enter the number of standard deviations to use for the Standard Deviation Stretch Method. (This option is enabled only if you have selected Standard Deviation as the Stretch Method.) Ignore Zeros in Input File When this check box is on, pixels with zero file values will be ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document.

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RGB Clustering

➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about RGB clustering, see the “Classification” chapter in the ERDAS Field Guide.

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RGB Cluster

RGB Cluster This dialog allows you to perform RGB clustering on one or more input image files. RGB clustering can be used to compress three bands of data into one, or to perform a simple unsupervised classification. It is often used to rescale 24-bit data to 8-bit data. This dialog is opened when you select Image Interpreter | Utilities... | Adv. RGB Clustering... . The Advanced RGB Clustering utility plots the pixels from 3 selected input bands into a 3dimensional feature space. Then a 3D grid is used to partition the space into clusters. You then set a minimum threshold on the clusters, so only clusters that are as large as the threshold will become output classes. Pixels which do not fall into any of the remaining clusters are assigned to the cluster with the smallest city-block distance from the pixel. The city-block distance is calculated as the sum of the distances in the red, green, and blue directions of the 3-dimensional space. There are 4 steps to performing RGB clustering: 2. Partitioning Input Data. 3. Adjusting Parameters for desired number of classes. 4. Building Lookup Table. 5. Creating Output Files. To partition input data (step 1),select an input file, and the bands to be used for Red, Green, and Blue. Then, load the image data into the partitions. To adjust parameters (step 2), group the initial Red, Green, and Blue partitions into sections, and set a minimum threshold. These parameters can be adjusted manually until the desired number of output classes is obtained (typically 256 for 8-bit output). It is also possible to select the number of sections you want to use, and automatically compute a threshold. This threshold contains the number of output classes closest to (but not larger than) the specified number of classes Raising the threshold reduces the number of output classes. Using fewer sections also lowers the number of output classes by reducing the number of blocks used in the 3D grid. However, there are some cases where using fewer sections increases the number of output classes. This increase occurs when blocks which were below the threshold individually are joined together; they then exceed the set threshold. There is a trade off between lowering the number of sections and raising the threshold. The use of more sections allows more available color gradations in the output file, while larger thresholds can cause small sections of unique coloration to be lost.

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RGB Cluster To build a lookup table (step 3), the software builds from the 3-D grid into the output set of classes using the city-block distance calculation described above. To create output files (step 4), map an input file through the lookup table built in step 3. This creates an output thematic file. Multiple files can be mapped through the same lookup table. Each output file will have the same resulting color scheme, which is useful for mosaicking these files later. At any time, the current state of the program can be saved. More files can be added to your set of partitioned data, or the lookup table can be re-used at a later time. The interface guides you through the steps by only enabling the appropriate options at each step. For instance, you cannot start adjusting parameters until at least one image has been partitioned. You must compute the number of classes before you can build the lookup table. And once the lookup table is built, you cannot change parameters unless the lookup table is cleared.

Image I/O Many of the parts on this tab are used both during step1, Partitioning Input Data, and also in step 4, Creating Output Files. Input File: File for data input. This is used for both the name of input to be partitioned and for the names of files to be run through the lookup table to create an output. Layers: The number of layers in the input file Get From List Each time an image is entered as an input file, the name of the image is added to the list of input images. This button, which is only enabled after the lookup table is built, will successively retrieve the names of these images from the list of image names, and enter it as the Input File for step 4. This allows you to easily run each image that was partitioned in step 1 to be run through the lookup table in step 4. Output Image File: Select output file. This is only used in step 4. Data Type: Displays the data type for output. The type is based on number of classes, which is determined by the setting of the Section and Threshold Parameters. Input Layer to Color: Red: Select the band to represent the red color gun. Green: Select the band to represent the green color gun. Blue: Select the band to represent the blue color gun. Coordinate Type: Map Choose the coordinate type for the rectangular subset. File Choose the coordinate type for the rectangular subset.

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RGB Cluster From Inquire Box Retrieve the coordinates from the Viewer Inquire Box. Subset Definition: UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate Skip Factor: X: Number of pixels to skip in x while loading data into partitions. Used in step 1 only. Y: Number of pixels to skip in y while loading data into partitions. Used in step 1 only. Load Image Data Load input image data into partition data. This starts the processing of the input data into partitions. Set AOI ... Select an area of interest to bound the processing. Batch Run the input file through the lookup table to create an output file in batch mode. Only enabled for step 4. Produce Output Run the input file through the lookup table to an create output file

Partition Data Number of Partitions: This is the number of initial partitions into which data is read. The default is 32.

☞ Note: This number may not be changed after any data has been partitioned. If you wish to change this value, it should be changed before selecting an input file and bands to be partioned. Red Sections: Number of sections to split partitions into for red. Maximum is 32. Green Sections: Number of sections to split partitions into for green. Maximum is 32. Blue Sections: Number of sections to split partitions into for blue. Maximum is 32. Total Pixel Count: Displays the total number of pixels read into partitions from all input files. Threshold Count: Minimum number of pixels for cluster to be counted as a class. Changing this value will also change the Threshold Percent.

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RGB Cluster Threshold Percent: Minimum percentage of pixels for the cluster to be counted as a class. Changing this value will also change the Threshold Count. This value is the Threshold Count divided by the Total Pixel Count x100. Number of Classes: Displays the number of classes based on the current sections and threshold. Data Type: Displays the data type for an output based on the number of classes. Calculate Number of Classes Calculate the current number of classes based on the current sections and threshold. This is dIsabled if auto-calculation is in effect. Auto-calculate classes Automatically recalculates the number of classes when any threshold or number of section parameters is changed. Optimize threshold for classes Adjusts the threshold, without changing the section count, until classes are as close as possible to specified number without exceeding it. Clear All Partition Data Deletes all currently loaded partition data. This returns you to the initial state before any data has been loaded into the partitons. Lookup Table: Build LUT Build lookup table for clustering input data. This can only be done after the number of classes has been calculated. Clear LUT Delete lookup table and re-enable parameter modification. This allows you to re-adjust parameters for the same input file. Partition & Lookup Table I/O: Read... Read partition data and/or lookup table from the file, and merge with current data. The data you read must have been partitoned using the same number of initial partitions as the data you currently have partitioned. Save Save partition data and/or lookup table to file. Save As... Save partition data and/or lookup table to a named file.

Input List This tab contains the list of input images. Input Images: Displays the list of images that were input into the partitions in step 1. The Get From List button will successively retrieve names of images from this list.

State: Displays the current state of the process.

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RGB Cluster

Close Exit this dialog. Help Display this On-Line Help file.

166

Layer Selection and Stacking

Layer Selection and Stacking This dialog allows you to stack layers from different images in any order. The stacked layers are saved to an .img file. To open this dialog, select Image Interpreter | Utilities... | Layer Stack....

Input File: Enter the name of the input file to be stacked in the layer. The default file extension is .img. Layer: Left-hold this popup list to select the layer(s) from the file above to include in the stack. Layer 1 is selected by default. (stack list) As you select layers, you can add them to the list below by clicking Add. Continue to select files and layers until you have as many stacked as you desire. Add Click to add the selected layer(s) to the stack list. The items in the stack list are gray because they are not editable. However, you can clear the list and select different files and layers. Clear

Click to clear the stack list. All entries are removed.

Output File: Enter the name of the output file. The .img extension will be added automatically.

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output Options: This group lets you select options for the output file. Union

Click to use the image area of both input files in this process.

Intersection process.

Click to use only the image area that both files have in common for this

Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file.

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Layer Selection and Stacking

AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Subset

Subset This dialog enables you to copy a selected portion, or subset, of an input data file into an output data file. It is opened when you select Image Interpreter | Utilities... | Subset... . This dialog can also be opened when you select Data Preparation | Subset Image....

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

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Subset

Data Type: This group gives information about the input and output file data types. Input: Output:

Shows the input file data type. Click the popup list button to select the data type for the output file.

Output: Select the appropriate output file type. Thematic

The output will be a thematic raster layer.

Continuous

The output will be a continuous raster layer.

Output Options: This group contains options for the output file Number of Input layers:

The number of layers in the input file is displayed.

Select Layers: Enter the layers to input as a comma separated list, for example: 1,3,5. Or enter a range of layers using a colon, for example: 2:5. Ignore Zero in Output Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

➲ For more information on why certain pixels are contained within a polygon when performing a Subset with an AOI, see the On-Line Help for Rules for Pixel Inclusion within Polygons.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

➲ For more information about subsetting, see the “Raster Data” chapter in the ERDAS Field Guide.

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Create File

Create File This dialog makes it easy to create a new IMAGINE file. You may define the size and content. To open this dialog, select Image Interpreter | Utilities...| Create File... . It can also be opened from the DataPrep menu.

Output File: Enter the name of the output file or click on the File Selector button. The default file extension is .img.

Size: The size of the new file may be numerically entered or derived from the dimensions of the Inquire Box in a Viewer. Columns: Enter the number of columns in new file. The default value is 512. Rows: Enter the number of rows in new file. The default value is 512.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Area Definition: Use this group to define a rectangular area for the output file. The coordinates of the area may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the area. The default coordinates are (0,0) and (511,511). From Inquire Box Click to define the area of the new fie by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

i

The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

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Create File LR Y: Lower Right Y coordinate

Cell Size: This group is enabled only for Map coordinates X Cell: Enter the width of cells in the new file. Y Cell: Enter the height of cells in the new file. Units: Click on the popup list button to select the units of cell dimension. Meters Feet Inches Centimeters Points Square Cells Click this checkbox to make cell height equal to cell width.

Data Type: This group gives information about the output file data types. Output:

Click the popup list button to select the data type for the output file.

Output: Select the appropriate output file type. Thematic

The output will be a thematic raster layer.

Continuous

The output will be a continuous raster layer.

Output Options: Number of Output layers: Enter the number of layers to create in the new file. Initialization value: Enter the value to use to initialize new file. Every cell is given this value.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog.

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Create File

View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Rescale

Rescale This dialog allows you to rescale data in any bit format as input and output. It is opened when you select Image Interpreter | Utilities... | Rescale... .

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Data Type: This group gives information about the input and output file data types.

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Rescale Input:

Shows the input file data type.

Output:

Click the popup list button to select the data type for the output file.

Input Range Options: This group lets you identify the range of data values to be used in this function. Minimum-Maximum Click to use a min-max stretch to identify the range of data values to be rescaled. Standard Deviation Click to apply a standard deviation stretch to identify the range of data values to be rescaled, then enter the number of standard deviations to use.

Output Range: This group lets you specify the range of data values to be output. Min:

Enter the minimum value data to be output.

Max:

Enter the maximum value data to be output.

Ignore Value for Minimum Calculation? Turn on this check box and the specified value will be ignored in the Minimum calculation. Enter the value to be ignored in the number field below the check box.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Mask

Mask This dialog enables you to use an .img file to select (mask) specific areas from a corresponding raster file and uses those areas to create one or more new files. The areas to mask are selected by class value. To open this dialog, select Image Interpreter | Utilities... | Mask... .

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Input Mask File: Enter the name of the .img file to use as a mask or click on the File Selector button. Setup Recode ... Click to recode the data values in the input file. The Thematic Recode dialog is opened.

Window: Union

Select the area of the files to process. Click to use the image area of both input files in this process.

Intersection process.

Click to use only the image area that both files have in common for this

Output File: Enter the name of the output file or click on the File Selector button. The .img extension will be added automatically.

Data Type: This group gives information about the input and output file data types. Input #1:

Shows the input file #1 data type.

Input #2:

Shows the input file #2 (input mask) data type.

Output:

Click the popup list button to select the data type for the output file.

Ignore Zero in Stats. When this check box is on, pixels with zero file values are ignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog.

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Mask

View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Image Degradation

Image Degradation This dialog enables you to reduce the resolution of an image by an integer factor in the X and Y directions. Degrade averages all of the original “small” pixels that make up the new “big” pixels. If the X and Y factors are large, this method will take more of the original pixels into account in the computation than a bilinear interpolation or cubic convolution resample would, since these resampling methods use only a small window for computation. This dialog is opened when you select Degrade... from the Utilities menu of Image Interpreter.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added. Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate

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Image Degradation LR Y: Lower Right Y coordinate

Scaling Factor: Enter a scaling factor by which to degrade the image. X Scale:

Enter the scaling factor by which to degrade the image in the X direction.

Y Scale:

Enter the scaling factor by which to degrade the image in the Y direction.

Exclude Background Value Click this checkbox to exclude a particular value from the output file.

Value to Exclude:

Enter the value to exclude.

OK Click to run this program with the options selected and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Replace Bad Lines

Replace Bad Lines This dialog enables you to remove bad lines or columns in raster imagery. This dialog is opened when you select Replace Bad Lines... from the Image Interpreter Utilities menu.

Input File: Enter the name of the input file or click on the File Selector button. The default file extension is .img. Output File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. If the input file does not have map coordinates, the coordinate type will automatically default to File. Map

Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper left corner.

Subset Definition: Use this group to define a rectangular area of the data to be used as the output file. The coordinates of the subset may be derived from an inquire box in the Viewer or by entering explicit X,Y values for the upper left and lower right corners of the subset. The default coordinates are the entire input file. From Inquire Box Click to define a subset area of the data by using the Viewer Inquire Box. When you click this button, the coordinates below are updated with the coordinates of the cursor box in the Viewer. To change these coordinates, you can move and/or resize the cursor box in the Viewer, then click this button again.

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The image you are using and the inquire box must already be displayed in a Viewer in order to use the From Inquire Box option. Otherwise, you may manually enter coordinates in the fields below. UL X: Upper Left X coordinate UL Y: Upper Left Y coordinate LR X: Lower Right X coordinate LR Y: Lower Right Y coordinate

Output Options: Specify how to replace the bad lines.

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Replace Bad Lines Replace Bad: Click to specify whether you want to replace bad lines (rows) or columns. Lines

Click to replace bad lines (rows).

Columns By:

Click to replace bad columns.

Click the popup list button to select how to calculate the new lines or columns.

Average Each bad line will be replaced by the average of the lines directly above and directly below it. If you are replacing columns, this option will average the columns to the left and right of the bad column. Copy Line Above Each bad line will be replaced by a copy of the line directly above it. If you are replacing columns, this option will copy the column to the left of the bad column. Copy Line Below Each bad line will be replaced by a copy of the line directly below it. If you are replacing columns, this option will copy the column to the right of the bad column. Enter Bad Line (Column) Numbers: Enter the line or column numbers containing bad lines. These are the lines that you want to replace. Ignore Zero in Output Stats.

Click to ignore zeros when statistics are calculated.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. View ... Click this button and a Model Maker window is opened and the graphical model used for this function is displayed. You can edit the graphical model from this Model Maker window for a specific use. You can also edit the Spatial Modeler Language script through the Model Maker window (select Process | Generate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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Vector to Raster

Vector to Raster This dialog allows you to convert different types of vector data into different types of raster data. To open this dialog, select Image Interpreter | Utilities... | Vector to Raster....

Input Vector File: Enter the name of the input vector file or click on the File Selector button. The default is .arcinfo coverage. To search for all coverages, type *.arcinfo. To search for shapefiles, type *.shp.

Vector Type: Specify the type of features to be converted: Polygon

Convert polygon features to raster.

➲ For more information see Rules for Pixel Inclusion within Polygons. Line Point

Convert line features (Arcs) to raster. Convert point features to raster.

Use Attribute As Value: Select an item from the feature attribute table to be the cell value of the output raster. The default is the internal ID.

Output Image File: Enter the name of the output file or click on the File Selector button. The .img extension is automatically added.

Output Data Type: Data Type: Click the popup list button to select the data type for the output file. Layer Type: Select the appropriate output file type. Thematic

The output will be a thematic raster layer.

Continuous

The output will be a continuous raster layer.

Ignore Zero in Stats. Ignore the zero value for statistics in the output file. From Inquire Box Retrieve the coordinates from the Viewer Inquire Box. Size Definition: UL X: Enter the upper left X coordinate. UL Y: Enter the upper left Y coordinate. LR X: Enter the lower right X coordinate

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Vector to Raster LR Y: Enter the lower right Y coordinate. Cell Size: X: Enter the X cell size of output pixels. Y: Enter the Y cell size of output pixels. Square Cells Click button to make X and Y cells sizes the same. Units: Select to use Meters or Feet for rasterizing input vector data into output raster. Meters Feet Layer Width: Enter the width in pixels of area to be written. Layer Height: Enter the height in pixels of area to be written.

OK Click to run this program with the options selected and close this dialog. Batch Click to include this function in a batch file. AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select an AOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog. Help Click to see this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

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