Viewer

Viewer 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.

Viewer On-Line Manual Viewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Recomputing Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

New Arc Coverage Layer Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 New SDE Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 New Shapefile Layer Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 View to Image File Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Choose Screen/Color Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Set View Extent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Print . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Raster Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Vector Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Annotation Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 TerraModel Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Three-Band Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Multi-Band Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Save Functional Layer As . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Save Layer As . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Image Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Moving an Inquire Cursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

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Viewer On-Line Manual Inquire Cursor Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Inquire Box Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Inquire Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Inquire Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Measurement Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Save As . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Set Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Measure Map Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Viewer Blend/Fade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Viewer Swipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Viewer Flicker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Arrange Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Window Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Split Viewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Set Zoom Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Viewer - Linear Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Rotate Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

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Viewer On-Line Manual Background Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Frame Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 View Extent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Box Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Ellipse Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Oval Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Point Edit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Poly Edit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 RotBox Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Simple Arc Edit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Choose Symbology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Symbol Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Select Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 New Palette . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Add Palette . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Select Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 About the IMAGINE Viewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

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Viewer On-Line Manual Starting a Viewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 The Viewer Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Opening Data Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Changing the Viewer Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Resampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Scrolling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Zooming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Animated Zoom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Box Zoom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Real-Time Zoom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Zoom Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Viewing Multiple Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Overlapping Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Non-Overlapping Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Quick View Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Inquiry Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Active Pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Moving an Inquire Cursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Zooming or Warping the Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Moving and Resizing an Inquire Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Zooming or Warping the Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Linking Viewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Making a Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Image Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Screen Pixels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Primary Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Color Guns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Brightness Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Bits for Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

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Viewer On-Line Manual Colormaps and Lookup Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Colormap vs. Lookup Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 ERDAS IMAGINE and Lookup Tables . . . . . . . . . . . . . . . . . . . . . . . . 106

IMAGINE Viewer vs. ERDAS Ver. 7.X Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Gray Scale Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Gray Scale Lookup Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Contrast Stretch and Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Pseudo Color Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Lookup Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Color Schemes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Gray Scale Color Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

True Color Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 True Color Lookup Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Statistics for Contrast Stretch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 Layer to Color Gun Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

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Viewer

Viewer An IMAGINE Viewer is started automatically when ERDAS IMAGINE starts. You may start additional Viewers by clicking the Viewer icon (shown below) on the IMAGINE icon panel.

The Viewer menu bar is opened across the top of every Viewer window. You can left-hold on each word on this menu bar to access a pull-down menu of ERDAS IMAGINE operations that are performed in the Viewer. Many commonly used Viewer functions are also accessible from the Quick View menu that appears when you right-hold in a Viewer. The Viewer can be resized by dragging any corner.

File New This submenu contains options for creating new layers in an existing viewer and for creating new viewers. AOI Layer Select this option to create a new AOI (area of interest) layer. Vector Layer... Select this option to create a new vector layer. The File Selector dialog is opened. Annotation Layer... Select this option to create a new annotation layer. The File Selector dialog is opened. Viewer Select this option to create a new viewer with specified visuals. Viewer Specified... Select this option to create a new viewer with the default visuals. The Choose Screen/Color Mode dialog is opened. Map Composition... Select this option to create a new map composition. The New Map Composition dialog is opened. Open

This submenu contains options for opening existing files.

AOI Layer... Select this option to open an existing AOI (.aoi) layer. The File Selector dialog is opened. Raster Layer... Select this option to open an existing Raster (.img) layer. The File Selector dialog is opened.

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Viewer Vector Layer... Select this option to open an existing Vector (Arc Coverage) layer. The File Selector dialog is opened. Annotation Layer... Select this option to open an existing Annotation (.ovr) layer. The File Selector dialog is opened. TerraModel Layer... Select this option to open an existing TerraModel (.pro) layer. The File Selector dialog is opened. View... Select this option to open an existing View (.vue) layer. The File Selector dialog is opened. Map Composition... Select this option to open an existing Map Composition (.map). The File Selector dialog is opened. Three Layer Arrangement... Select this option to open a Three-Band Layer (.img). The File Selector dialog is opened. Three-Band Layer

☞ The results of selecting File | Open | Three Layer with more than one Viewer window open, or if selected from a Viewer other than Viewer #1. Multi Layer Arrangement... Select this option to open a Multi Layer (.img) file. The File Selector dialog is opened.

☞ The results of selecting File | Open | Multi Layer with more than one Viewer window open, or if selected from a Viewer other than Viewer #1. Save

This submenu contains options for saving one or more layers.

Top Layer Select this option to save changes to the top layer displayed in the Viewer. Upon closing the Viewer, you are prompted to save each modified layer.

☞ NOTE: Image files opened in Relief can not be saved. Top Layer As... Select this option to save changes to the top layer displayed in the Viewer as a different file. The Save Layer As dialog is opened. AOI Layer As... Select this option to save changes to the AOI layer displayed in the Viewer as a different file. The Save AOI As dialog is opened. All Layers Select this option to save all layers in the viewer. View... Select this option to save the Viewer as a .vue file for use with the VUE Player. The File Selector dialog is opened. View to Image File... Select this option to save the image in a viewer to a 3 band RGB file. The File Selector dialog is opened. Select the output file type from the Files of Type: popup list. Use the Options tab to select the area to use and output file size. 2

Viewer Print... Select this option to print the contents of the viewer. The Print dialog is opened. Clear

Select this option to clear all data from the Viewer, but leave the Viewer running.

Close Select this option to quit this Viewer. Unmodified layers are closed immediately. You are prompted to save each modified layer. Other Viewers remain running, and ERDAS IMAGINE remains running. Close Other Viewers Select this option to closes all Viewers except the one from which you select this option.

Utility Inquire Cursor... Select this option to open the Inquire Cursor dialog and place a crosshair cursor over the image in the Viewer. Inquire Box... Select this option to open the Inquire Box Coordinates dialog and place a query box over the image in the Viewer. Inquire Color... Select this option to select the inquire cursor color. The Inquire Color dialog is opened. Inquire Shape... Select this option to change the shape of the cursor. The Inquire Shape dialog is opened. Inquire Home Select this option to move the cursor to the center of the displayed portion of the image. Measure... Select this option to measure points, lines, and areas in the Viewer. The Measurement Tool is opened. Selector Properties... Select this option to display or change properties for the current selector. The Rotbox Editor dialog is opened if the current selector is an inquire box. The Point Edit dialog is opened if the current selector is a an inquire cursor. Pick Properties... Select this option while you are digitizing a polyline or polygon to view the Poly Edit dialog. This is the same as pressing the space-bar while digitiging. Blend... Select this option to blend or fade two images or layers together. The Viewer Blend/Fade dialog is opened. Swipe... Select this option to view portions of the top and bottom images (layers) in a Viewer at the same time. The Viewer Swipe dialog is opened. Flicker... Select this option to quickly flip between the top and bottom layers in the Viewer. The Viewer Flicker dialog is opened.

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Viewer Layer Info... Select this option to view information about the top layer in the Viewer. If the top layer is an .img file, the Image Info dialog is opened with the top layer in the Viewer loaded. If the top layer is a vector coverage, the VectorInfo dialog is opened. HFA Info... Select this option to view the IMAGINE hierarchical data structure of the top layer displayed in the Viewer. The Hierarchical File Viewer dialog is opened. This data structure is described in detail in the ERDAS Field Guide. Image Drape... Start Image Drape with Displayed DEM. VirtualGIS... Start VirtualGIS with Displayed DEM. This option available only with addon module.

View ☞ Screen transformations in the View menu work in a cumulative manner. They do not reset every time you click Apply. Arrange Layers... Select this option to rearrange the layers displayed in the Viewer. The Arrange Layers dialog is opened. Create Magnifier... Select this option to start a new Viewer with the same data displayed at a zoom ratio of 2 X the zoom ratio in the Viewer. Tile Viewers Select this option to rearrange the Viewers on the screen. This option is designed for use when there are two or more Viewers open. It rearranges the Viewers so that none overlap. Window Information... Select to display information about the window visual of the current Viewer. The Window Information dialog is opened. Split... Select this option to create new Viewers by splitting the current Viewer. The new Viewer(s) will be empty. Split Vertical Select this option to create a new Viewer by splitting the current Viewer in half vertically. Split Horizontal Select this option to create a new Viewer by splitting the current Viewer in half horizontally. Split ... Select this option to split the Viewer bi-directionally. The Split Viewer dialog is opened. Zoom Select this option to reduce, magnify, and zoom in on a particular area. The zoom is based on the center of the displayed portion of the image. See also Real-Time Zoom.

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Viewer To zoom based on a user-selected portion of the image, use the Rotate and Magnify option or the Box Zoom feature. In By 2 Select this option to quickly magnify the displayed data. Multiplies the current zoom ratio by 2. Out By 2 Select this option to quickly reduce the displayed data. Divides the current zoom ratio by 2. In By X... Select this option to specify a custom zoom. This option may also be used to change the resampling method used by many features such as zoom, rotate, pan, etc. The Set Zoom Ratio dialog is opened. Out By X... Select this option to specify a custom reduction factor. This option may also be used to change the resampling method used by many features such as zoom, rotate, pan, etc. The Reduction dialog is opened. Default In the Viewer, left-hold to reset the zoom ratio to 1. Any annotation or vector data is reset to register with the raster layers. If annotation or vector is displayed with no raster layers, then the zoom ratio is reset to its original value when the data were displayed. In the Map Composer, left-hold to set the zoom ratio to “actual size,” as it would appear when printed. Rotate and Magnify Select this option to rotate and/or magnify an area of the displayed layer. A resizeable box is displayed in the Viewer window. -- to move and position the box, left-hold the mouse in the box and drag the cursor. -- to resize the box, left-hold and drag the handles on the corners or sides of the box. -- to rotate the box, middle-hold (UNIX only), or control-left-hold (Windows only) inside the box and drag in the direction you want to rotate.

➲ When the box is rotated in the desired direction, and you double-click inside the box, the rotation is reversed. This is because the rotation occurs specific to the parameters of the box. The top line of the box always represents the top. You can also modify the position and rotation angle of the box by pressing the space bar to display the RotBox Editor dialog. When you have the box positioned and sized the way you want it, double-Click inside the box and the area will be rotated as described above and magnified to fill the viewer.

i

You may also use the real-time rotation feature of the Roam tool

to rotate an image.

5

Viewer Scale Image To Window Select this option to resize the image to the viewer size. Window To Image Select this option to resize the viewer to the image size. Extent... Select this option to define the area of the image to view. The View Extent dialog is opened. Scale Tool... Select this option to change the scale of the displayed image. The Frame Scale dialog is opened. Rotate... Select this option to rotate the layer in the Viewer. The Rotate dialog is opened. Using this dialog has no effect on the file unless you save it. Rotate/Flip/Stretch... Select this option to scale, offset, rotate, and/or reflect the image in the Viewer. The Viewer - Linear Adjustment dialog is opened. North Arrow Turn on this check box to enable a north arrow to be displayed in the Viewer window. Use the North Arrow preferences in the viewer category of the Preference Editor to set the default for this option. Scale Bar Turn on this check box to enable a scale bar to be displayed in the Viewer window. Use the Scale Bar preference in the viewer category of the Preference Editor to set the default for this option. Virtual Roaming Turn on this check box to enable the scrollbar to continuously render the image displayed in the Viewer. Link/Unlink Viewers

Select this option to link or unlink Viewer windows.

Geographical Select this option to link Viewers geographically so that the same image area is opened in all linked Viewers. This type of link will not reflect changes in the arrangement of the layers, band combinations, or changes by other tools in the Viewer. Select this option again to unlink. Spectral Select this option to link Viewers spectrally so that any enhancements made to an image will also be made in other Viewers if that same image, or portions of it, are displayed in other Viewers. Select this option again to unlink. Background Color... Select this option to change the background color of the Viewer. The Background Color dialog is opened. Status Bar Turn on this check box to enable the single-line help which displays at the bottom of the Viewer window. Use the Preference Editor to set the default for this option.

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Viewer Scroll Bars This check box turns the Viewer scroll bars on or off. Turning off the scroll bars increases your display area. Use the Preference Editor to set the default for this option. Menu Bar This check box turns the Viewer menu bar on or off. Turning off the menu bar increases your display area. Use the Preference Editor to set the default for this option. Tool Bar Turn on this check box to enable the row of Viewer icon tools which displays at the top of the Viewer window. Use the Preference Editor to set the default for this option. Borders This check box creates or deletes the border around the outside of the Viewer. Use the Preference Editor to set the default for this option.

AOI Tools... Select this option to open the AOI tool palette. Undo Select to undo the last edit. Select multiple times to undo a series of edits (back to the last saved version of this AOI layer). Cut Select to delete the selected element(s). A copy is kept in a copy/paste buffer. Delete Raster Mask Select to delete all raster areas from the AOI layer. Raster areas are created by using the AOI | Copy Selection to AOI... option of the Viewer menu bar from a pseudo color image. Group Select to combine the selected elements into a group element. Ungroup Select to break a group element into single elements. Reshape Select to reshape a selected polygon or polyline:

♦ hold to move a vertex of the polygon or polyline; ♦ middle-click to add a vertex to the polygon or polyline; ♦ shift-middle-click to add or remove a vertex from the polygon or polyline; ♦ hold on any side of a polygon to move it without rotating. To quit reshape mode, click outside the element or select another element. Invert Polygon Select to invert a region grown area so that everything not in the region grow is selected as an AOI. This option is helpful for selecting island polygons.

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Viewer Element Properties... Select to bring up the Properties dialog for the selected element:

♦ Ellipse ♦ Rectangle ♦ Polygon/Polyline ♦ Point ♦ Group Styles... Select this option to define the default styles for AOIs using the AOI Styles dialog. Seed Properties... Select this option to select a model or “seed” pixel(s) to start a region growing AOI. This method is often used to select training samples prior to classification. The Seed Properties dialog is opened. Copy Selection To AOI... Select this option to add the selected areas to a new or existing AOI layer in this or another Viewer. Link

Select this option to link the AOI in this window to the specified AOI.

Tablet Input Select this option to use a digitizing tablet to select areas of interest. The Viewer must contain an AOI layer for this option to be enabled. New Configuration... Select this option to set up a new configuration. The Tablet Setup dialog is opened. Current Configuration... Select this option to use the current configuration. The Tablet Setup dialog is opened.

Raster Tools... Select this option to open the Raster tool palette. Undo Click to undo the last edit. Click multiple times to undo a series of edits (back to the last saved version of this raster layer). Copy Select this option to copy the area enclosed by the currently selected AOI to a paste buffer. Paste... Select this option to paste a previously copied raster area into the viewer. The Raster Paste dialog is opened.

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Viewer Band Combinations... Select this option to change band combinations. If you are viewing a single band of data, the Set Layer Combinations (single-band display) dialog is opened. If you are viewing multiple bands of data, the Set Layer Combinations (multiband display) dialog is opened. Pixel Transparency... Select this option to change raster background transparency. The Set Transparency dialog is opened. Set Resampling Method... Select this option to set the resampling method used by the current raster layer. The Set Resampling Method dialog is opened. Data Scaling... Select this option to change spectral data scaling. The Set Data Scaling dialog is opened. Contrast Histogram Equalize Select this option to equalize the histogram using 256 bins. Standard Deviation Stretch Select this option to apply a standard deviation stretch of 2 to the histogram. General Contrast... Select this option to open the Contrast Adjustment dialog. The Histogram Equalization method selected by default. Brightness/Contrast... Select this option open the Contrast/Brightness Tool dialog. Piecewise Contrast... Select this option to open the Piecewise Contrast Tool dialog. Breakpoints... Select this option to open the Breakpoint Editor dialog. Load Breakpoints... Select this option to open a File Selector dialog to load breakpoints from file. Save Breakpoints... Select this option to open a File Selector dialog to save breakpoints to file. Filtering Smooth Select this option apply a 3X3 low pass filter to the image display. Sharpen Select this option to apply a 3X3 edge enhance filter to the image display. Find Edges Select this option to apply a 3X3 edge detect filter to the image display. Convolution Filtering... Select this option open the general Convolution dialog.

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Viewer Statistical Filtering... Select this option to perform statistical filtering on the image. The Neighborhood Functions dialog is opened. Recode... Select this option to open the Thematic Recode dialog. Fill... Select this option to open the Area Fill dialog. Offset Values... Select this option to open the Area Offset dialog. Interpolate... Select this option to perform a local surface interpolation on the selected AOI. The Interpolation dialog is opened. Recompute Statistics Click to recompute histogram and statistics for the top raster layer in the Viewer. The Recompute Statistics function does not affect thematic raster layers. (More...) Attributes... Select this option to open the Raster Attribute Editor dialog. Geometric Correction... Select this option to geocorrect the image. The Set Geometric Model dialog is opened. Set Drop Point... Select this option to make a single point shift to geocorrect the image. The Image Offset dialog is opened. Profile Tools... Select this option to open the Select Profile Tool dialog. Relief Shading Tool... Select this option to open the Relief Tool dialog. The top layer must contain an image that was loaded with the Display as: Relief option.

Vector Enable Editing Tools...

Select this option to enable vector editing.

Select this option to bring up the Vector Tools dialog.

Undo Select this option to undo the last edit or all edits performed since the layer was saved. Simply Click Undo as many times as needed to undo any number of edits. Cut Select this option to cut the selected elements from the coverage and save them to the paste buffer. These items can be restored using the Paste command or the Undo button. Copy Select this option to copy the selected features to the paste buffer. Paste Select this option to paste the items stored in the paste buffer. (Write items to the paste buffer using either the Cut or Copy commands.)

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Viewer Items are pasted in the same location as the items in the buffer. Therefore if you select a line, copy it, then paste it into the same layer, it will be placed exactly on top of the original line. You must move it if that is not where you want it. This makes it very easy to select a group of features in one coverage and use that same group in another layer and maintain the same level of accuracy. For example, you may want to use county boundaries from one layer in a related layer. Delete Select this option to delete the selected items from the layer. Deleted items are not stored in the paste buffer and can only be restored using the Undo command. Reshape Select this option to change the shape of a single element.

♦ left-hold to move a vertex; ♦ middle-click to add a vertex; ♦ shift-middle-click to add or remove a vertex; ♦ left-hold on any side of a polygon or segment of a polyline to move it without rotating. To quit reshape mode, Click outside the element or select another element. Spline Select this option to smooth the selected arcs according to the grain tolerance that is stored with the coverage, or that you specify in the Options dialog. Vertices are added to the line according to the grain tolerance specified. The shape of the lines will change when Spline is used. Densify Select this option to smooth the selected arcs according to the grain tolerance that is stored with the coverage, or that you specify in the Options dialog. Vertices are added to the line according to the grain tolerance specified. The shape of the lines will change when Spline is used. Densify does not change the shape of the lines. Generalize Select this option to eliminate unnecessary vertices in a line according to the weed tolerance stored with the layer or that you enter in the Options dialog. Performing Generalize may speed further processing since the number of vertices in the layer may be greatly reduced. Join Select this option to combine two arcs that share a node, if they are the only two lines sharing that node. The combined lines cannot have more than 500 points. Group Select this option to create a single multi-part feature by grouping the selected features.

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Viewer Ungroup Select this option to break up a selected multi-part feature into its component parts. Attributes... Select this option to view the attributes of the currently displayed vector layer in the Vector Attribute Table dialog. Viewing Properties... Select this option to display or edit vector properties. The Properties dialog is opened. Symbology... Select this option to show and define vector symbology using the Symbology dialog. Options... Select this option to show and set vector snap distances and tolerances using the Options dialog. Seed Properties... Select this option to specify a model or “seed” pixel(s) to start a region growing polygon. The Seed Properties dialog is opened. Copy Selection To Vector... Select this option to add the selected objects to a vector layer. The vector layer to which you are adding elements must be displayed. Tablet Input Select this option to digitize new vector information using a digitizing tablet. New Configuration... Select this option to set up a new configuration. The Tablet Setup dialog is opened. Current Configuration... Select this option to use the current configuration. The Tablet Setup dialog is opened.

Annotation Tools... Select this option to open the Annotation tools palette. Undo Select this option to undo the last edit. Select multiple times to undo a series of edits (back to the last saved version of this annotation layer). Cut Select this option to delete the selected element(s). A copy is kept in the copy/paste buffer. Copy Select this option to make a copy of the selected element(s) in the copy/paste buffer. Paste Select this option to paste the contents of the copy/paste buffer to the same location. Select the copied element and move it to the desired location. Group Select this option to combine the selected elements into a single group element.

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Viewer Ungroup Select this option to break a group element into individual constituent elements. Reshape Select this option to reshape a selected polygon, polyline, arc, or AOI. This option also lets you create or reshape the invisible polyline that text may follow:

♦ left-hold to move a vertex of the polygon, polyline or text polyline; ♦ middle-click to add a vertex to the polygon, polyline or text polyline; ♦ shift-middle-click to add or remove a vertex from the polygon, polyline or text polyline;

♦ left-hold on any side of a polygon or segment of a polyline or text polyline to move it without rotating. To quit reshape mode, Click outside the element or select another element. To enter precise size and positioning coordinates when reshaping an arc, press the space bar after clicking Reshape to bring up the Ellipse Editor dialog. Raise To the Front Click to move the selected element(s) in front of all others in the drawing order. Forward by One Click to move the selected element(s) forward by one rank in the drawing order. Lower To the Back Click to move the selected element(s) behind all others in the drawing order. Backward by One Click to move the selected element(s) back by one rank in the drawing order. Distribute Vertically Click to evenly distribute the centers of selected elements vertically between the top element and the bottom element. Horizontally Click to evenly distribute the centers of selected elements horizontally between the right element and the left element. Flip Vertically Click to flip selected annotation vertically.

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Viewer Horizontally Click to flip selected annotation horizontally. Align Object North Select this option to align selected annotation toward north. Alignment... Select this option to align selected annotation objects. The Align dialog is opened. Element Properties... Click to open the Properties dialog for the selected element:

♦ Text ♦ Ellipse ♦ Arc ♦ Rectangle ♦ Polygon/Polyline ♦ Symbol ♦ Map frame ♦ Group Styles... Select this option to open the Annotation Styles dialog. Attributes... Select this option to open the Annotation Attributes dialog. Seed Properties... Select this option to specify a model or “seed” pixel(s) to start a region growing polygon. The Seed Properties dialog is opened. Copy Selection To Annotation... Select this option to add the selected objects to an annotation layer. The annotation layer to which you are adding elements must be displayed. Tablet Input

Select this option to digitize new annotation using a digitizing tablet.

New Configuration... Select this option to set up a new configuration. The Tablet Setup dialog is opened. Current Configuration... Select this option to use the current configuration. The Tablet Setup dialog is opened.

TerraModel Palette... Select this option to choose a color scheme to use with the project file. The Select Colors dialog is opened. 14

Viewer Select Layer... Select this option to choose which data layers from the project file to display in the Viewer. The Select Layers dialog is opened.

Help Help for Viewer

Select this option to see this On-Line Help document.

Click to open a raster layer. The File Selector dialog is opened.

Click to close the top layer opened in the Viewer.

Click to display the Image Info dialog if the top layer in the Viewer is an .img file and the VectorInfo dialog if the top layer is a vector coverage.

Click to save the top layer in the Viewer.

Click to print the contents of the Viewer.

Click to clear the Viewer.

Click to reset the image to a zoom factor of 1.0.

Click to zoom in by two from the center of the displayed portion of the image. See also Animated Zoom.

Click to zoom out by two from the center of the displayed portion of the image. See also Animated Zoom.

Click to measure points, lines, and areas in the displayed layer. The Measurement Tool is opened.

15

Viewer

Click to start/update the inquire cursor. The Inquire Cursor dialog is opened if it is not already open.

Click to display the tool palette for top layer.

Click to start the Profile tools. The Select Profile Tool dialog is opened.

Click to reset the window tools.

Click for zoom re-center, box zoom and real-time zoom features. For zoom re-center, left-click in the Viewer to indicate the center of the enlarged area. For Box zoom, left-hold and drag a box in the Viewer. For real-time zoom, middle-hold (or Ctrl-left-hold) and drag up and down in Viewer. See Zooming.

Click for zoom re-center, box zoom and real-time zoom features. For zoom re-center, left-click in the Viewer to indicate the center of the reduced area. For Box zoom, left-hold and drag a box in the Viewer. For real-time zoom, middle-hold (or Ctrl-left-hold) and drag up and down in Viewer. See Zooming.

Click to roam the image. Left-hold and drag the hand-shaped cursor over the image to pan up, down, left, and right. Middle-hold (or Ctrl-Left-hold) and drag to rotate the image in real-time.

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

➲ See the ERDAS IMAGINE Tour Guides for step-by-step instructions on many Viewer functions.

➲ For theoretical information about how images are opened, see the “Image Display” chapter in the ERDAS Field Guide.

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Viewer

Recomputing Statistics For athematic raster layers, the histogram and statistics are computed for the entire image using all pixels and excluding no values. The computations use the bin function from the descriptor table unless a new bin function has been created using the Set Data Scaling dialog. If no bin function exists for the layer, the computations will be based on a default bin function created from the original, unedited layer as described in the Default Bin Functions table below. Any edits made to the image (pending or saved) are considered in the computations. The new histogram and statistics are used by the raster Data Scaling, Histogram Equalize, Standard Deviation Stretch and Contrast Adjust tools and the Breakpoint Editor the next time the tools are invoked. When statistics are recomputed for a layer that has no defined bin function, one of the following methods is used: Stats

Data Range

Binning Method

U1, U2, U4, U8

Y

N/A

Direct

Data Range

Data Range

U1, U2, U4, U8

N

N/A

Direct

Data Type Range

Data Type Range

S8, U16, S16, U32, S32

Y

0 - 255

Direct

Data Range

Data Range

S8, U16, S16, U32, S32

Y

Other

Linear

Data Range

Data Range

S8, U16, S16, U32, S32

N

N/A

Linear

0 - 255

256

F32, F64, C64, C128

Y

N/A

Linear

Data Range

256

F32, F64, C64, C128

N

N/A

Linear

0 - 255

256

Data Type *

Bin Range

# of Bins

* See Raster Data Types for a description of the abbreviations used in this column. For all other cases, linear binning of 256 bins from 0 to 255 is used. Data values outside that range are binned into the first or last bins.

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New Arc Coverage Layer Option

New Arc Coverage Layer Option This dialog is opened when you select File | New | Vector Layer... from the Viewer menu, select Arc Coverage from the Files of Type: list and then click OK in the file selector.

New Coverage Precision: Single Precision Double Precision

Click to create a single precision coverage. Click to create a double precision coverage.

OK Click to create the coverage and close this dialog. Cancel Click to cancel the coverage creation and close this dialog. Help Click to open this On-Line Help document.

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New SDE Layer

New SDE Layer This dialog presents a series of panels to assist you in creating a new SDE layer. Please read the information in the ERDAS IMAGINE Installation Guide regarding the configuration of your computer for use with an SDE server. This dialog is opened when you select File | New | Vector Layer... from the Viewer menu, select SDE Vector Layer from the Files of Type: list and then click OK in the file selector.

Cancel Click to cancel the creation of a new SDE layer and close the dialog. Click to move to the next panel. Finish Click to complete the creation of a new SDE layer. Help Click to display this help file. Connect to SDE Server To create an SDE layer, you must first establish a database connection to an SDE server.

SDE Connection: Select whether to create a new connection to the SDE server or use an existing connection if one is available. Create new

Establish a new connection to the SDE server.

Use existing

Use an existing SDE connection.

Specify connection info: This information is required only if the Create new radiobutton above is selected.Fill in necessary information to make a connection to the SDE server. SDE Server:

The machine on which the SDE server is running.

SDE Instance:

The name of the SDE instance. Default is “esri_sde”.

Username:

Your database user name.

Password:

Your database password.

Connect

Click here to initiate connection to the SDE server using above info.

Select an existing connection: This information is required only if the Use existing radiobutton above is selected. Use an existing connection to the SDE server.

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New SDE Layer Connections: Disconnect

A list of existing connections to the SDE server. Click here to disconnect the selected connection from the SDE server.

Select a Feature Table An SDE database containd one or many feature tables. They are displayed below in the format of [TableOwner].[TableName].[FeatureColumn].

Select a table to define the new layer: From a list of tables that contain a shape column, select one as the data source for the new SDE vector layer.

Select Attribute Tables Select attribute table(s) to join with the feature table. Tables are joined using a common key column. Double click an available table to see columns to the right.

Available Table List: From a list of attribute (or business) tables, select one or more to be joined with the feature table you have just selected. The columns of the attribute tables will become the attributes of the new SDE vector layer.

Columns in Table: A list of columns for the attribute table you have just double clicked on the table list on the left. You can examine the column list of a table to see whether it shares a common key column with the feature table so that they may be joined to create the new SDE vector layer.

--> Add an attribute table to the Selected Table List on the right. <-- Remove an attribute table from the Selected Table List on the right. Selected Table List A list of tables (a feature table and additional attribute tables) to be joined to constitute the data source of the new SDE vector layer.

Join Feature and Attribute Tables Join tables by specifying a JOIN statement of key columns, such as “Table1.Column1=Table2.Column2”. Use “and” between statements.

Double click for columns: You can double click a table to see its columns. Columns: A list of columns for the table you have just double clicked. JOIN Statement: The clause to be used to join the tables together. = Put an equal sign into the JOIN Statement. 20

New SDE Layer

and Use this to append additional equal statements. Clear Clear the join clause. Specify SQL Where Clause Specify an SQL Where Clause for attribute constraints.

Tables: A list of tables you have selected for the new SDE vector layer. Double click a table name to see the columns on the right.

Columns: A list of columns for the table (on the left) you have just double clicked. Compares: Select a comparision operator to be put into the where clause. (keypad) Use this keypad to enter numeric values, arithmetic operators in the where clause.

and Use this to append additional constraints to the where clause. or Use this to specify a SQL “or” operator to the where clause. not Use this to specify a SQL “not” operator to the where clause. Clear Clear the text from the SQL Where Clause field. SQL Where Clause A constraint to be imposed in the SQL query to the database so that only a subset of rows (or records) will be extracted from the feature table (and the attribute tables if selected).

Select Attribute Columns to Display Select a subset of columns to be displayed as attributes of the SDE layer.

Table to select columns from: Select a table here to have its columns displayed below.

(cellarray) Click in the Selected field to determine whether a column should be displayed as an attribute column of the new SDE vector layer.

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New Shapefile Layer Option

New Shapefile Layer Option This dialog is opened when you select File | New | Vector Layer... from the Viewer menu, select Shapefile from the Files of Type: list and then click OK in the file selector.

Select Shapefile Type: Select a shape type for the new shapefile. A shapefile can only contain one type of shapes. Arc Shape

A shape type of arcs composed of one or more polylines.

Point Shape A shape type of a single points (x, y pairs). Polygon Shape A shape type of polygons composed of one or more rings. Multipoint Shape A shape type of points or point groups. 3D Point Shape A shape type of three dimensional points. 3D Arc Shape A shape type of three dimensional polylines. 3D Polygon Shape A shape type of three dimensional polygons. 3D Multipoints A shape type of three dimensional point or point groups. Measured Point A shape type of points with measurement values. Measured Arc

A shape type of polylines with measurement values

Measured Polygon Measured Multipoint

A shape type of polygons with measurement values. A shape type of points or point groups with measurement value

OK Create Shapefile Layer Cancel Cancel new shapefile creation. Help Click to open this On-Line Help document.

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View to Image File Options

View to Image File Options This tab lets you set parameters for saving the data currently displayed in the Viewer to an .img file. By default, this .img file will be a 3-band (RGB) file, regardless of how many bands are in the data set. If, however, Gray Scale is enabled, the .img file will contain only one band. Not everything opened in a viewer can be converted to .img. The exceptions are:

♦ AOI ♦ Shaded Relief through viewer ♦ Transparency across frames ☞ Enhancements to the image file in the Viewer must be saved in order to be included in the output file. You must use the Edit | Compute Statistics function in Image Info to create statistics for the new file before it can be enhanced. Select File | View to Image File... from the Viewer menu bar then click the Options tab to open this dialog.

Area to Use: Select area of viewer to use in output image file. Full Click to save the entire image (including any part not visible in the Viewer) to an .img file. Visible Click to save just the part of the image that is visible in the Viewer to an .img file.

Output Image Size: Width at: (percentage) is (number) Pixels Use these number fields to specify the width of the output image as a percentage of the original, or in pixels. Height at: (percentage) is (number) Pixels Use these number fields to specify the height of the output image as a percentage of the original, or in pixels. Maintain Aspect Ratio Select this checkbox to hold the ratio of width to height constant as the output image size is adjusted.

Use Gray Scale Output: Select this checkbox to output to gray scale (a singleband image).

Help Click to view this help file.

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Choose Screen/Color Mode

Choose Screen/Color Mode This dialog allows you to select the display type of a new Viewer, such as TrueColor, DirectColor, etc. This dialog is opened when you select File | New | Viewer Specified... from the Viewer menu bar.

☞ Creating a new Viewer with new display attributes is supported under UNIX only. Screens/Color Modes Click on the popup list button to select the display type. The options that are displayed depend on your system configuration.

OK Click to use the selected display type 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.

➲ See the “Image Display” chapter in the ERDAS Field Guide for more information about display devices.

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Set View Extent

Set View Extent This dialog allows you to define the area of the image to view by typing in upper left and lower right corner coordinates of the portion of the image you want to view. This dialog is opened when you click the Set View Extent check box in the Raster Options of the File Selector dialog.

ULX: Enter the upper left X coordinate of the portion of the image you want to view. ULY: Enter the upper left Y coordinate of the portion of the image you want to view. LRX: Enter the lower right X coordinate of the portion of the image you want to view. LRY: Enter the lower right Y coordinate of the portion of the image you want to view. File Coords Click to specify the coordinates in file coordinates. Map Coords Click to specify the coordinates in map coordinates. OK Click to use these coordinates and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to open this On-Line Help document. ➲ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINE Interface manual.

25

Print

Print This dialog enables you to print using a specific map template applied to a specific map area. This dialog opens when you select File | Print... from the IMAGINE Viewer menu bar.

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The Viewer Print tool prints the data from saved files. Unsaved edits are not printed.

Map Template: Select one of the template options below: Landscape Select this option to use a default template for landscape orientation. Portrait Select this option to use a default template for portrait orientation. Other Select this option to specify a pre-defined template. Enter the template name or click the File Selector button.

Area to Print: Full Select this option to print the entire image area. Subset Select this option to print a subset of the entire image area. ULX: Upper Left X Map Coordinate of Subset Area ULY: Upper Left Y Map Coordinate of Subset Area LRX: Lower Right X Map Coordinate of Subset Area LRY: Lower Right Y Map Coordinate of Subset Area Select Area... Select Subset Area from Box

OK Click this button to accept the parameters. The Print Map Composition dialog is opened. Preview... Click to view the image you are about to print in a map composition window. Cancel Click to cancel the operation and close the dialog. Help Click to open this help file.

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Raster Options

Raster Options This file tab is accessible from the Select Layer To Add dialog that is accessed via File | Open | Raster Layer... from the Viewer menu bar. Clicking the Options tab enables you to select from a variety of raster options to apply to the image you are about to display.

Raster Options Choose from the raster options below. Display as : Click on this popup list to select the color mapping method from the following selections: True Color Click to display the selected image in true color mode. True color display is appropriate for most interval or ratio multi-layer images. Pseudo Color Click to display the selected image in pseudo color mode. Pseudo color is appropriate for nominal or ordinal images in one layer. Gray Scale Click to display the selected image in gray scale mode. Gray scale is appropriate for a single layer of interval or ratio data. Relief Click to display the selected image as a shaded relief layer. This option is appropriate only for gray scale layers. When a layer is displayed using this option, you can click the Tool icon on the Viewer tool bar or select Raster | Relief Shading Tool... to bring up the Relief Tool dialog. Layers to Colors: This group is opened if you select multilayer data (a layerset) and True Color display. Select the layer to color gun assignments for multilayer data. Use the Preference Editor to set the default for this option. Red: Green: Blue:

Enter the layer to display in the red color gun. Enter the layer to display in the green color gun. Enter the layer to display in the blue color gun.

Display Layer: This group is opened if you choose to display multilayer data as Pseudo Color, Gray Scale, Relief, or if you select a single layer image. Layer:

Select the layer of the layerset to display.

Orient Image to Map System Viewer.

Click to resample loaded image when displaying in the

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Raster Options If the check box is not activated (gray), the Viewer will display the image in the image's file coordinate system with file coordinate 0, 0 at the upper left of the view and the X coordinate increasing from right to left and the Y coordinate increasing from top to bottom of the view. Map coordinates may still be read in the status bar of the Viewer and with the Inquire Cursor. If the check box is activated, the Viewer will display the image in the map coordinate system associated with the image layers in the file. In this case, the map coordinate mapmin-x, map-max-y will be placed at the upper left of the view and the X map coordinate will increase from right to left and the Y map coordinate will decrease from top to bottom of the view. Map-min-x and map-max-y are obtained from the map bounding box of the image. The pixel size selected for viewing the image is as specified in the MapInfo section of the ImageInfo dialog. Clear Display If this check box is on, the Viewer will be cleared before new data are displayed. Otherwise, the new data will be displayed on top of any currently displayed data. Fit to Frame If this check box is on, the image will be magnified or reduced to fit the Viewer window at its current size. Data Scaling Normally when grayscale and true color data are displayed, a linear stretch from 0 - 255 is applied to the entire range of data. Click to specify an alternate range in which to stretch the data. When you click OK, the Set Data Scaling dialog is opened. This dialog shows a histogram of the data file values and allows you to enter the minimum and maximum data file values to display. No Stretch

Click to display data without applying the normal 0 - 255 linear stretch.

Set View Extent Click to specify the upper left and lower right coordinates of the portion of the image to display. The Set View Extent dialog is opened. Background Transparent Click to make the background of true color and gray scale areas transparent so that the layer underneath will show. This option clips black areas from displayed images and is especially helpful when displaying images that will be mosaicked. Zoom by: Using: Help

If Fit to Frame is off, then you can enter the zoom ratio for the data

Choose from a set of interpolation methods. Click to view the On-Line Help for this file tab.

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Vector Options

Vector Options This Options tab is accessed from a file selector dialog, which enables you to open or create a vector coverage in a Viewer. This Options tab is opened when you select File | Open | Vector Layer... or when you select File| New | Vector Layer...from the Viewer menu bar and then click on Vector Options.

Vector Options Use Symbology Click to use symbology for displaying vector data. Clear Display Click to clear the Viewer window before displaying vector data. Option: If the Use Symbology checkbox is enabled, the current vector symbology file is listed. Set ... Click to set up the symbology for this vector layer. The Choose Symbology dialog is opened. Help

Click to view the On-Line Help for this Options tab.

➲ For more information on using a digitizing tablet to create vector data, see the Digitizing Tips section of the IMAGINE Interface manual

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Annotation Options

Annotation Options This file tab is accessible from the Select Layer To Add dialog that is accessed via File | Open | Annotation Layer... from the Viewer menu bar. Clicking the Options tab in the Select Layer To Add dialog enables you to access the Clear Display option for the annotation.

Annotation Options Select or deselect the following annotation option: Clear Display Turn on this check box to clear the Viewer window before displaying annotation. Help

Click to view the On-Line Help for this dialog.

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TerraModel Options

TerraModel Options This tab is accessible from the Select Layer To Add dialog that is accessed via File | Open | TerraModel Layer... from the Viewer menu bar. Clicking the Options tab in the Select Layer To Add dialog enables you to access the Clear Display option for the TerraModel.

Options Select or deselect the following TerraModel option: Clear Display Turn on this check box to clear the Viewer window before displaying annotation. Help

Click to view the On-Line Help for this tab.

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Three-Band Options

Three-Band Options This Options tab is accessed through the Open Three Layer dialog, which enables you to automatically open four Viewers; one Viewer for a true color image, plus three additional Viewers — one for each of the layers assigned to the red, green, and blue color guns. The red, green, and blue layers are displayed in gray scale. The four Viewers are automatically linked. This Options tab is opened when you select File | Open | Three Layer Arrangement... from the Viewer menu bar and then click on Options.

Options Display: Select the type of image from the following selections: True Color Click to display the selected image in true color mode. True color is appropriate for most interval or ratio (continuous) multi-layer images. Pseudo Color Click to display the selected image in pseudo color mode. Pseudo color is appropriate for nominal or ordinal (thematic) images in one layer. If this option is chosen, then one layer is displayed in pseudo color and there is no three-layer display. Gray Scale Click to display the selected image in gray scale mode. Gray scale is appropriate for a single layer of interval or ratio data. If this option is chosen, then one layer is displayed in gray scale and there is no three-layer display.

Layers to Colors: This group is opened if you select multilayer data (a layerset) and True Color display. Select the layer to color gun assignments for multi-layer data. Red Green Blue

Enter the layer to display in the red color gun. Enter the layer to display in the green color gun. Enter the layer to display in the blue color gun.

Display Layer: This group is opened if you choose to display multilayer data as pseudo color or gray scale, or if you select a single-layer image. Layer:

Select the layer of the layerset to display.

Number of Layers

Shows the number of layers of the selected image file.

Clear Display Turn on this check box to erase any data that are already displayed in the Viewer. Otherwise, data will be displayed on top of the currently displayed data, and will be magnified or reduced (if necessary) to register to it and fit in the Viewer window. Help

Click to display On-Line Help for this Options tab.

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Three-Band Options

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

➲ For more information about how images are opened, see the “Image Display” chapter in the ERDAS Field Guide.

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Multi-Band Options

Multi-Band Options This file tab is accessible from the Open Multi Layer dialog, accessed via File | Open | Multi Layer Arrangement... from the Viewer menu bar. Clicking the Options tab in the Open Multi Layer dialog enables you to select the display and color options for the image.

Options Select from the options below. Display: Select the color mapping method from the following selections: True Color Click to display the selected image in true color mode. True color display is appropriate for most interval or ratio multi-layer images. Pseudo Color Click to display the selected image in pseudo color mode. Pseudo color is appropriate for nominal or ordinal images in one layer. Gray Scale Click to display the selected image in gray scale mode. Gray scale is appropriate for a single layer of interval or ratio data. Layers to Colors: This group is opened if you select multilayer data (a layerset) and True Color display. Select the layer to color gun assignments for multilayer data. Use the Preference Editor to set the default for this option. Red: Green: Blue:

Enter the layer to display in the red color gun. Enter the layer to display in the green color gun. Enter the layer to display in the blue color gun.

Display Layer: This group is opened if you choose to display multilayer data as Pseudo Color, Gray Scale, Relief, or if you select a single layer image. Layer:

Select the layer of the layerset to display.

Number of Layers: The number of layers in the image is displayed. Clear Display Click to clear the image currently displayed in the Viewer when the new image displays. Help

Click to view the On-Line Help for these options.

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Save Functional Layer As

Save Functional Layer As This dialog lets you save a functional layer to a new file. A functional layer is a function of the Signature Editor and the underlying image, such as Image Alarm, Threshold, or Image to Feature Space. The layer is saved as a pseudo color file. To use this dialog, left-hold File | Save | Top Layer As... in the Viewer menu bar with the functional layer you want to save displayed on top. When the Verify Save on Close dialog is opened, answer Yes.

Save Functional as: Use the file name part to enter a name for the new file. OK Click to save the functional layer 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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Save Layer As

Save Layer As This dialog enables you to save the top layer displayed in a Viewer to a new file. It is opened when you select File | Save | Top Layer As... from the Viewer menu bar. This dialog is also opened when you select Save Layer As from the right-button menu of a layer bar in the Arrange Layers dialog.

☞ If you have the same raster or annotation layer displayed in more than one Viewer, then Save As will save only the layer in the current Viewer as a new file. The other Viewers will contain the old file. This is not true for vector layers however. If the same vector layer is displayed in more than one Viewer, Save As works on all views of that layer.

Save as: Use this file name part to enter a name for the new file. The default file extension depends on the type of layer you are saving.

OK Click to save the layer to the specified 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.

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Image Information

Image Information This dialog gives you individual pixel information by using a cursor which displays as a cross-hair in the Viewer window. The Viewer window which is under inquiry will be listed in the Inquire Cursor dialog title bar (e.g., Viewer #1: lanier.img). The Inquire Cursor dialog can be accessed two ways (an image must be displayed in the Viewer):

♦ Select the Inquire Cursor... option of the Quick View right button menu ♦ Left-hold Utility | Inquire Cursor from the Viewer menu bar ☞ If a cursor seems to disappear when moving it, go to the Preference Editor and turn off the Fast Selectors preference.

(coordinate type) Left-hold this first popup list and select the type of coordinates in which to display the image information. Map Show the map coordinates. If the data are georeferenced, the coordinates are displayed. If the image is registered to another image, the coordinates are displayed in the units of the other image’s map-to-layer-pixel transformation. Otherwise, coordinates in the default pixel map system are shown. File Show the file coordinates, which are pixels, starting with 0,0 in the upper left corner. Lat/Lon

Show Latitude/Longitude coordinates, if the data are geocoded.

Paper Show the units this area would be on paper if data were printed. The origin (0,0) of the paper coordinate system is in the lower left corner.

X: X coordinate value or the cursor position. Y: Y coordinate value of the cursor position. (units) This label shows the type of units in which the coordinates are measured. Left-click on this icon to display the inquire cursor information for the next linked Viewer at the same location.

Projection: Shows the map projection system and the spheroid to which the data are rectified.

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Image Information

(CellArray) This CellArray shows information for each layer in the file. If the lock icon is set, this information will automatically update as the Inquire Cursor is moved. Otherwise, the information is updated when the Inquire Cursor is stopped (not moving). Right-hold in the Row column for the Row Selection popup. Right-hold on any column heading for the Column Options popup. The information which is displayed for continuous and thematic data will be slightly different: Continuous Data Band - this column shows which layers are assigned the red, green, and blue color guns (the layers that are displayed in the Viewer) FILE PIXEL - the actual pixel value from the file LUT VALUE - lookup table value for the pixel HISTOGRAM - number of pixels (histogram) in the image that have this pixel value Thematic Data Pixel Value - the actual pixel value from the file CLASS NAMES - shows the name of the pixel classification RED, GREEN, and BLUE - shows the actual LUT values for the pixel

Left-click to move the inquire cursor up by the specified number of units.

Left-click to move the inquire cursor down by the specified number of units.

Left-click to move the inquire cursor to the center of the Viewer.

Left-click to move the cursor to the left by the number of units entered in the meter number to the right.

Left-click to move the cursor to the right by the number of units entered in the meter number to the right.

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Image Information

When this icon is displayed, the CellArray information is updated continuously as you drag the inquire cursor in the Viewer. Left-click this icon to toggle the previous icon.

When this icon is displayed, the CellArray information is updated when you release the mouse button after moving the inquire cursor. Left-click this icon to toggle the following icon.

(increment meter number) This meter number controls the number of units that the arrow buttons will move the cursor.

(increment units popup list) Left-hold this popup list to select the units by which the arrow buttons will move the cursor.

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If the coordinate system in which the cursor’s increments have been set is switched, the increment size will revert to the default.

Map Increment Units File Increment Units Close Left-click to close this dialog and dismiss the inquire cursor. Help Left-click to see this On-Line Help document. Moving an Inquire Cursor To move an inquire cursor (cross-hairs), do any of the following:

♦ Left-hold the intersection of the cross-hairs and drag it to the desired location ♦ Enter the desired coordinates in the X: and Y: fields ♦ Use the four arrow icons to move the cursor by map or file units in any direction Inquire Cursor Attributes The color and shape of the Inquire Cursor can be changed for easier viewing. Color The color can be changed by left-holding Utility | Inquire Color... from the Viewer menu bar. The Inquire Color dialog is opened.

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Image Information Shape The shape of the inquire cursor can also be changed by selecting Utility | Inquire Shape... from the Viewer menu bar. The Inquire Shape dialog is opened.

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

➲ See the ERDAS IMAGINE Tour Guides for step-by-step instructions on using the Inquire Cursor.

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Inquire Box Coordinates

Inquire Box Coordinates Use this dialog to see the coordinates of the corners of an inquire Box, or to edit them by entering specific coordinates. To use the Inquire Box successfully, the image must be oriented to its map system, and no rotation should be applied to the Viewer.

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The Inquire Box does not necessarily represent a rectangular area orthogonal to the map system or file coordinates if the data beneath it is rotated or otherwise not oriented to the map system or file coordinates.

You can access the Inquire Box two different ways:

♦ Select the Inquire Box... option of the Quick View right-button menu ♦ Left-click Utility | Inquire Box from the Viewer menu bar The Viewer number from which you started the Inquire Box and the name of the top layer in that Viewer are reported in the title bar of this dialog.

ULX:

Shows the X coordinate of the upper left corner of the box.

ULY: Shows the Y coordinate of the upper left corner of the box. You can edit these values, and the box will move accordingly. If you move or resize the box in the Viewer, these values are dynamically updated.

LRX: Shows the X coordinate of the lower right corner of the box. LRY: Shows the Y coordinate of the lower right corner of the box. You can edit these values, and the box will move accordingly. If you move or resize the box in the Viewer, these values are dynamically updated.

Fit to AOI Left-click to fit the Inquire Box to the selected AOI. Type: Left-hold this popup list to select the type of coordinates for the box corners. Map

Show the map coordinates if the data are rectified.

File Show the file coordinates, which are pixels, starting with 0,0 in the upper left corner of the layer. Lat/Lon

Show Latitude/Longitude coordinates if the data are georeferenced.

Paper Show the units this area would be on paper if the data were printed. The origin (0,0) of the paper coordinate system is in the lower left corner of the layer.

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Inquire Box Coordinates

Units: The units for the selected coordinate type are shown. Apply Left-click to apply the selected box coordinates to the displayed image. If this is a linked image, you can left-click this button to change the display area in the other Viewer to the area inside the box.

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.

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Inquire Color

Inquire Color This dialog enables you to change the color of the inquire cursor or the inquire box. It is opened when you select Utility | Inquire Color... from the Viewer menu bar.

Inquire Color Click and hold this color patch to select a color for the cursor or box. Selecting Other... brings up the colorwheel.

OK Click to use the selected color for the cursor or box and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to open 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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Inquire Shape

Inquire Shape This dialog enables you to change the shape of the Inquire Cursor. It appears when you leftclick Utility | Inquire Shape... from the Viewer menu bar

Inquire Icon: This file name part lists the available icons for the inquire cursor shape (.cursor file extension). Left-click on the cursor shape you would like to use. Use Icon Left-click to use the icon entered in the file name part above as the inquire cursor shape.

Use Cursor Left-click to revert to using the default inquire cursor shape (cross hairs). Apply Left-click to apply the selected icon or cross hairs to the inquire cursor shape. Close Left-click to close this dialog with or without the cursor shape being changed. 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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Measurement Tool

Measurement Tool This dialog gives you tools for measuring areas in a Viewer. The measurements are written as text to a file which is opened in the Measurement Tool. This text can be saved, edited, and printed just like any other text file. The Viewer which is being measured is opened in the title bar of the Measurement Tool (e.g., Measurement Tool for Viewer #1). Select Utility | Measure... from the Viewer menu bar or click the to open this tool.

icon in the Viewer tool bar

File Click to save and print measurements and to close the Measurement Tool. The keyboard shortcut is Meta-f. Save

Click to save the measurements to a file. The keyboard shortcut is Ctl-s.

Save As... Click to save the measurements to a new file. The Save As dialog is opened. Print... Click to print the measurements. The Print dialog is opened. The keyboard shortcut is Ctl-p. Close

Click to close the measurement tool. The keyboard shortcut is Ctl-d.

Edit Click to edit the text in the Measurement Tool. The keyboard shortcut is Meta-e. Copy

Click to copy the selected text. The keyboard shortcut is Ctl-c.

Use the keyboard Paste key to paste the text in the desired location of the Measurement Tool. Use the keyboard Delete key to cut text. Clear Last Measure Click to clear the last measurement from Viewer. This does not clear it from the text in the Measurement Tool. Use the Delete key to clear the text from the Measurement Tool. Set Units...

Click to change the units used for display. The Set Units dialog is opened.

Set Map Type... Click to specify the map type to use for displaying point measurements. The Measure Map Type dialog is opened. Tablet... opened

Click to use a digitizing tablet for measurements. The Tablet Setup dialog is

Help Click to open this On-Line Help document. The keyboard shortcut is Meta-h.

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Measurement Tool Help for Measure Displays Help for the Measurement Tool

Click to save the measurements to a file. The Save As dialog opens.

Click to print the measurements. The Print dialog opens.

Click to copy highlighted measurements. Use the keyboard Paste key to paste the text in the desired position.

Click to disable the current Measurement Tool.

Click to measure points in the displayed image. Click the icon and then click in the Viewer to designate the point.

Click to measure lengths and angles in the displayed image. Click the icon and then click in the Viewer to add each vertex. Double-click or middle-click (depending upon how your preferences are set) to end the polyline.

Click to measure perimeters and areas in the displayed image. Click the icon and then click in the Viewer to add each vertex. Double-click or middle-click (depending upon how your preferences are set) to close the polygon.

Click measure rectangular areas in the displayed image. Click the icon, and then lefthold in the Viewer from the upper left to the lower right corner of the desired rectangle. Press the shift key while drawing to create a perfect square.

Click to measure ellipse-shaped areas in the displayed image. To draw the ellipse, click the icon, and then left-hold in the Viewer from the center to the lower right “corner” of the desired ellipse. Press the shift key while drawing to create a perfect circle.

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A box will display in the Viewer rather than an ellipse. However, the measurements are taken correctly from the ellipse area.

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Measurement Tool

When this icon is opened, the selected Measurement Tool will remain selected until you either select another tool or click this icon again, toggling this feature off. This allows you to take multiple measurements with the same tool.

When this icon is opened, the selected Measurement Tool will revert to the pointer tool after one measurement. If you click this icon, it will toggle to the previous icon.

measuretext: Measurement information is displayed in this edittext field before they are printed or saved to a file.

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

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Save As

Save As This dialog allows you to save a copy of the text in the Measurement Tool under a new name. This dialog opens when you select File | Save As... from the Measurement Tool menu bar.

Save file as: Use this filename part to enter the name of the file to be saved. The .mes extension will be added automatically. OK Click to save the file and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to open 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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Set Units

Set Units This dialog enables you to select the units for the measurements taken with the Measurement Tools. This dialog opens when you select Edit | Set Units... from the Measurement Tool menu bar.

Length: Click on the popup list button to select the type of units for the measurement in lengths. Inches Feet

Measurements will be in inches. Measurements will be in feet.

Yards

Measurements will be in yards.

Miles

Measurements will be in miles.

Centimeters Meters

Measurements will be in centimeters.

Measurements will be in meters.

Kilometers

Measurements will be in kilometers.

Area: Click on the popup list button to select the type of units for the area measurement. Sq Miles Acres

Area will be measured in square miles.

Area will be measured in acres.

Hectares

Area will be measured in hectares.

OK Click to reset and display measurements with new units and close this dialog. Cancel Click to close this dialog without making any changes. Help Click to open 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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Measure Map Type

Measure Map Type This dialog enables you to specify the map type to use for displaying point measurements. It is opened when you select Edit | Set Map Type... from the Measurement Tool menu bar.

Map Type: Click on the popup list button to select the map type to use for measuring point positions. These options are valid only if the layer is georeferenced. If it is not, file coordinates will be used regardless of what is selected here. Map

Use map coordinates.

Lat/Lon

Use Latitude/Longitude coordinates.

OK Click to use the selected option and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to open 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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Viewer Blend/Fade

Viewer Blend/Fade This dialog enables you to blend or fade two images or layers together. The two layers must both be opened in the same Viewer and must be registered to the same projection system. When this option is selected, the bottom layer is brought to the top.

☞ Before selecting this option, you should have the desired image area displayed in the Viewer. Once this dialog is opened, you can resize the Viewer, but the blend will affect only the originally opened area. This dialog is opened when you select Utility | Blend... in the Viewer menu bar.

Blend/Fade Percentage: Use the number field or the slider bar to determine how much of the top layer shows through the bottom layer. 0% means that the top layer is invisible. 50% means that the top layer is half visible and the bottom layer is half visible. 100% means that the bottom layer is invisible. Automatic Blend/Fade: You can select the Auto Mode if you want the blend/fade to run from 0 to 100 and back again continuously until you stop it. Auto Mode

Click to initiate auto mode. Click again to stop auto mode.

Speed: Time in milliseconds between frames. Lower numbers indicate shorter time and a faster swipe rate. The minimum value is 50.

Ok Click to close this dialog. Help Click to open 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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Viewer Swipe

Viewer Swipe This dialog enables you to view portions of the top and bottom images (layers) in a Viewer at the same time using a vertical or horizontal swipe line. The two layers must both be displayed in the same Viewer and must be registered to the same projection system. When this option is selected, the Viewer shows the top layer in the left half and the bottom layer in the right half.

☞ Before selecting this option, you should have the desired image area displayed in the Viewer. Once this dialog is opened, you can resize the Viewer, but the swipe will affect only the originally opened area. This dialog is opened when you select Utility | Swipe... from the Viewer menu bar.

Swipe Position: Use the number field or slider bar to control the percentage of each image that is visible. 0% means that the top layer is invisible and 100% means that the bottom layer is invisible.

Direction: Indicate whether the swipe line will be vertical or horizontal. Vertical

Click for a vertical swipe line. Top image slides left-to-right.

Horizontal

Click for a horizontal swipe line. Top image slides top-to-bottom.

Automatic Swipe: You can select the Auto Mode if you want the swipe to run from 0 to 100 and back again continuously until you stop it. Auto Mode

Click to initiate auto mode. Click again to stop auto mode.

Speed: Time in milliseconds between frames. Lower numbers indicate shorter time and thus faster swipe rate. The minimum value is 50.

Cancel Click to close this dialog. Help Click to open 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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Viewer Flicker

Viewer Flicker This dialog enables you to quickly switch between the top and bottom images (layers) in a Viewer. The two layers must both be opened in the same Viewer and must be registered to the same projection system.

☞ Before selecting this option, you should have the desired image area displayed in the Viewer. Once this dialog is opened, you can resize the Viewer, but the flicker will affect only the originally opened area. This dialog is opened when you select Utility | Flicker... in the Viewer menu bar.

Automatic Flicker: You can select the Auto Mode if you want the top and bottom layers to flicker back and forth until you stop it. Auto Mode

Click to initiate auto mode. Click again to stop auto mode.

Speed: Time in milliseconds between frames. Lower numbers indicate shorter time and thus faster swipe rate. The minimum value is 50.

Manual Flicker Click to bring the bottom layer to the top. Cancel Click to close this dialog. Help Click to open 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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Arrange Layers

Arrange Layers This dialog is an interactive “stacker” tool for arranging multiple layers that are opened in a viewer, or map frames and map annotation in a map composition. Each opened layer is represented by a bar in a scrolling list. You can rearrange these bars using the options described below. The top of the stack represents the top, or most visible layer in the Viewer. Lower layers will be obscured by any opaque regions in higher layers. This dialog is opened when you select View | Arrange Layers from the Viewer menu bar or Map Composer menu bar.

(stacker) Left-hold on any bar in the stack, and drag it to a new location in the stack. The following options are used with any layer in the stacker.

Apply Click to change the arrangement of layers in the Viewer or Map Composer according to your changes in this dialog. This button is disabled until you have edited the stack.

Reset Click to reset the layers to their original positions. This button is disabled until you have edited the stack.

Up This button is not enabled until you right-hold Frame Options/Descend Into in a map frame layer. It allows you to move up out of the map frame level and into the default state of the Arrange Layers dialog.

Close Click to close this dialog without arranging layers. Help Click to see this On-Line Help document.

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Arrange Layers

Layer Options (right button menu)

For each layer type, there is a menu of options

accessed through the right mouse button.

♦ Annotation Options ♦ AOI Options ♦ Frame Options ♦ Layer Options ♦ PseudoColor Options ♦ Relief Options ♦ TrueColor Options ♦ GrayScale Options ♦ Vector Options

Annotation Options The following options appear when you right-hold on an annotation layer. Raise To Top

Move this layer to the top of the stack.

Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer. Save Layer

Right-hold to save the layer.

Save Layer As... is opened. Layer Visibility

Right-hold to save the layer as a new file. The Save Layer As dialog Right-hold to toggle the visibility of the layer.

Set Current Layer Right-hold to specify this layer as the current layer for using the annotation editing commands such as Paste in which you do not have to have objects selected to perform the operation.

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Arrange Layers This is often used when you are creating a new layer by copying features from another layer in the Viewer. Show Attributes Right-hold to show the attributes of this annotation layer. The Annotation Attributes dialog is opened.

AOI Options The following options appear when you right-hold on an AOI layer. Raise To Top

Move this layer to the top of the stack.

Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer. Save Layer

Right-hold to save the layer.

Layer Visibility

Right-hold to toggle the visibility of the layer.

Frame Options The following option is opened when you right-hold on a map frame layer. Raise To Top

Move this layer to the top of the stack.

Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer. Descend Into

Right-hold to change the order of the layers inside the map frame.

To return to the initial format of the Arrange Layers dialog, Click the Up button at the bottom of the dialog.

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Arrange Layers

GrayScale Options The following options appear when you right-hold on a gray scale layer. Raise To Top

Move this layer to the top of the stack.

Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer. Save Layer

Right-hold to save the layer.

Save Layer As... is opened. Layer Visibility

Right-hold to save the layer as a new file. The Save Layer As dialog Right-hold to toggle the visibility of the layer.

Brightness/Contrast... Right-hold to adjust the brightness and contrast of the current layer. The Brightness/Contrast Tool dialog is opened. Piecewise Contrast... Right-hold to adjust the brightness and contrast of a specified range of the layer. The Piecewise Contrast Tool dialog is opened. Breakpoints... Right-hold to view, edit, and rescale the histograms and lookup table graphs.The Breakpoint Editor (Gray) dialog is opened. Band Combinations... Right-hold to change the displayed band of a multi-band image without reloading the file. The Set Layer Combinations (single-band display) dialog is opened.

Layer Options The following options appear when you right-hold on a functional layer. Raise To Top

Move this layer to the top of the stack.

Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer.

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Arrange Layers Save Layer

Right-hold to save the layer.

Layer Visibility

Right-hold to toggle the visibility of the layer.

PseudoColor Options The following options appear when you right-hold on a thematic or pseudo color layer. Raise To Top

Move this layer to the top of the stack.

Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer. Save Layer

Right-hold to save the layer.

Save Layer As... is opened. Layer Visibility

Right-hold to save the layer as a new file. The Save Layer As dialog Right-hold to toggle the visibility of the layer.

Attribute Editor...

Right-hold to bring up the Raster Attribute Editor for this layer.

Relief Options The following options appear when you right-hold on a relief layer. Raise To Top

Move this layer to the top of the stack.

Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer. Save Layer

Right-hold to save the layer.

Save Layer As... is opened.

Right-hold to save the layer as a new file. The Save Layer As dialog

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Arrange Layers Layer Visibility

Right-hold to toggle the visibility of the layer.

Relief Tool... Right-hold to use the Relief Tool to set sun azimuth and elevation and ambient light parameters.

TrueColor Options The following options appear when you right-hold on a true color layer. Raise To Top

Move this layer to the top of the stack.

Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer. Save Layer

Right-hold to save the layer.

Save Layer As... is opened. Layer Visibility

Right-hold to save the layer as a new file. The Save Layer As dialog Right-hold to toggle the visibility of the layer.

Brightness/Contrast... Right-hold to adjust the brightness and contrast of the current layer. The Brightness/Contrast Tool dialog is opened. Piecewise Contrast... Right-hold to adjust the brightness and contrast of a specified range of the layer. The Piecewise Contrast Tool dialog is opened. Breakpoints... Right-hold to view, edit, and rescale the histograms and lookup table graphs for the red, green, and blue color guns. The Breakpoint Editor dialog is opened. Band Combinations... Right-hold to change the layers (bands) that are displayed in Red, Green, and Blue on the monitor. The Set Layer Combinations (multi-band display) dialog is opened.

Vector Options The following options are displayed when you right-hold on a vector layer. Raise To Top

Move this layer to the top of the stack.

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Arrange Layers Lower To Bottom Delete Layer

Move this layer to the bottom of the stack.

Remove this layer from the Viewer or Map Composer.

Until you click Apply, the bar will be shaded, and the layer will remain in the Viewer or Map Composer. When you click Apply, the layer is removed. This option does NOT delete the layer from the hard disk, only from the Viewer. Save Layer

Right-hold to save the layer.

Save Layer As... is opened.

Right-hold to save the layer as a new file. The Save Layer As dialog

Layer Visibility

Right-hold to toggle the visibility of the layer.

Enable Editing

Right-hold to edit this vector layer.

Set Current Layer Right-hold to specify this layer as the current layer for vector editing commands such as Paste in which you do not have to have objects selected to perform the operation. This is often used when you are creating a new layer by copying features from another layer in the Viewer. Show Attributes vector layer.

Right-hold to bring up the Vector Attribute Table for the current

Show Properties

Right-hold to bring up the Properties dialog for the current layer.

Show Symbology Show Options

Right-hold to bring up the Symbology dialog for the current layer.

Right-hold to bring up the Options dialog for the current layer.

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

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Window Information

Window Information The Window Information dialog shows the type of image displayed in the Viewer window. .Mode: Displays the type of image, such as truecolor, pseudocolor, or directcolor, used in the Viewer window.

Depth: Displays the color depth of the image in the Viewer window. For example, 24 bit or 8 bit.

Screen: Displays the monitor screen number of the image used in the Viewer window. Close Click to close this dialog. Help Click to show the On-line Help for this dialog.

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Split Viewer

Split Viewer This dialog gives you options for splitting a Viewer window into two or more Viewers. In effect, new Viewers are started and arranged on the screen. The new Viewers will be created over the area occupied by the original Viewer and are sized accordingly. The new Viewers that are created do not contain any data, but the original Viewer retains any data that were displayed in it. This dialog is opened when you select View | Split | Split from the Viewer menu bar.

Split Direction: Select from the following options for the direction of the split. vertical Click to divide the current Viewer vertically. The resulting Viewers will all be side by side. horizontal Click to divide the current Viewer horizontally. The resulting Viewers will all be stacked. bidirectional Click to divide the current Viewer vertically and horizontally, resulting in Viewers arranged in a “windowpane” fashion.

Number of Windows: Enter the total number of Viewer windows that you want to result from the split.

OK Click to start the process and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to open 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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Set Zoom Ratio

Set Zoom Ratio This dialog provides an interactive way to magnify (or reduce) the data in the Viewer by setting the zoom ratio. This dialog is opened when you select View | Zoom | In By X from the Viewer menu bar.

Zoom Ratio: Enter the zoom ratio. Resampling Method: Select the Resampling method to apply to the top raster layer in the Viewer. All other layers zoomed in the Viewer retain the resample method with which they were opened.

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To change only the resampling method, the zoom ratio must be set to 1.00. Click on the popup list button to select the resampling method to use. The options are described below: Nearest Neighbor

Use the value of the closest pixel to assign to the output pixel value.

Bilinear Interpolation Use the data file values of four pixels in a 2 x 2 window to calculate an output value with a bilinear function. Cubic Convolution Use the data file values of 16 pixels in a 4 x 4 window to calculate an output value with a cubic function.

➲ Resampling is discussed in detail in the “Rectification” chapter of the ERDAS Field Guide. OK Click to zoom the image and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to open 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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Viewer - Linear Adjustment

Viewer - Linear Adjustment This dialog lets you make quick, linear (1st-order) geometric corrections to an image that is opened in the Viewer. The parameters of the linear adjustments can be entered into the Affine Model Properties dialog to be used for rectification. This dialog is opened when you select Rotate/Flip/Stretch from the View menu of the Viewer menu bar.

File to Screen Transformation Options: This group lets you specify the linear adjustment in terms of scale, offset, rotation, and reflection. Transformation takes place when the Apply button is clicked. In the Viewer, scale is the same as zoom, except that here you have the option to set X and Y scale independently. If you use the Zoom options in the Viewer, you will undo any changes to the scale that you do here and vice-versa.

Scale:

Use the scale parameters to affect the size of the image in the X and Y directions.

X 1: Set X scaling. Y 1: Set Y scaling. Both 1: This field lets you set the X and Y scale to the same value.

➲ Values greater than 1 (one) enlarge the image size. Values less than 1 (one) reduce the image size. Negative values rotate the image 180 degrees while enlarging or reducing.

Offset: Use the offset parameters to move the image by a number of pixels in the X and/ or Y directions. X:

Set X offset.

Y:

Set Y offset.

➲ When applying an offset of 100.00 to the Viewer, it moves the current imagery to an offset defined in the Offset X and Offset Y directions from the upper left corner of the Viewer window. The area above and to the left of the imagery is filled in with background color, which appears as black space.

Rotate Angle: Enter the number of degrees by which you want to rotate the image. See also the Positive Rotation Direction controls, below.

➲ Rotation always occurs around the center pixel of the image. 64

Viewer - Linear Adjustment

Initialize Left-click to reset all of the Transformation Options to their initial values, which specifies a scale of 1 (one), no offset, and no rotation.

Positive Rotation Direction: Select which direction a positive (over zero) rotation angle will rotate the image. Counter-Clockwise If this radio button is on, then a positive rotation angle will rotate the image counterclockwise, and a negative angle will rotate it clockwise. Clockwise If this radio button is on, then a positive rotation angle will rotate the image clockwise, and a negative angle will rotate it counterclockwise.

Reflect Options: Use these icons to select the direction(s) in which to reflect the image. Reflection takes place when the Apply button is clicked.

Click to turn off reflection.

Click for left-to-right reflection. NOTE: Text objects cannot be reflected.Text objects are rotated 180 degrees.

Click for top-to-bottom reflection. NOTE: Text objects cannot be reflected.Text objects are not rotated.

Click for top-to-bottom and left-to-right reflection. (This has the same effect on the data as a 180 degree rotation.)

Apply Click to apply the specified adjustments to the image in the Viewer, and keep this dialog.

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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Rotate Image

Rotate Image This dialog lets you rotate the data in the Viewer. It is opened when you select View | Rotate... from the Viewer menu bar.

Rotation Angle (deg.): Enter the number of degrees to rotate the image. The default positive rotation direction when this dialog is opened is controlled by the Positive Rotation Direction preference in the User Interface and Session category of the Preference Editor dialog. However, you can set the positive direction of rotation using the Positive Direction controls. Rotation always occurs around the center pixel of the image.

Positive Direction: Select which direction a positive (over zero) rotation angle will rotate the image. Counterclockwise If this radio button is on, then a positive rotation angle will rotate the image counterclockwise, and a negative angle will rotate it clockwise. Clockwise If this radio button is on, then a positive rotation angle will rotate the image clockwise, and a negative angle will rotate it counterclockwise.

Apply Click to apply the specified rotation to the image in the Viewer and keep this dialog. Close Click to cancel this process and close this dialog. Help Click to open 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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Background Color

Background Color This dialog enables you to change the background color of the Viewer. This option is helpful for displaying annotation. For example, you may want to view an annotation layer in which the elements are black. These elements would not be visible in a black Viewer unless you changed the styles of the elements. Using this option, you can change the background to white and these elements will be visible. This dialog is opened when you select View | Background Color in a Viewer menu bar or when you select Background Color from the Quick View menu (right-hold with your cursor in the Viewer).

Background Color: Click and hold this color patch to select the background color. Selecting Other will bring up the colorwheel.

OK Click to use the selected color for the Viewer background and close this dialog. Empty Viewers will not change to this color, but the background of annotation layers displayed after this option is set will show the selected color.

Cancel Click to cancel this process and close this dialog. Help Click to open 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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Frame Scale

Frame Scale This dialog allows you to change the scale of the displayed image. It is opened when you select View | Scale | Scale Tool... in the Viewer menu bar.

Scale 1: Enter the scale at which to redisplay the image. The current scale of the image is shown as the default.

Apply Click to redisplay the image at the specified scale. Close Click to close this dialog. Help Click to open 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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View Extent

View Extent This dialog allows you to define the area of the image to view by typing in upper left and lower right corner coordinates of the portion of the image you want to view. This dialog is opened when you select View | Scale | Extent from the Viewer menu bar.

ULX: Enter the upper left X coordinate of the portion of the image you want to view. ULY: Enter the upper left Y coordinate of the portion of the image you want to view. LRX: Enter the lower right X coordinate of the portion of the image you want to view. LRY: Enter the lower right Y coordinate of the portion of the image you want to view. File Coords Click to specify the coordinates in file coordinates. Map Coords Click to specify the coordinates in map coordinates. OK Click to use these coordinates and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to open 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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Reduction

Reduction This dialog provides an interactive way to reduce (zoom out) the data in the Viewer. This dialog prompts you for a reduction factor, which is the reciprocal of the zoom ratio. For example, a zoom ratio of 0.5 is a reduction factor of 2, which reduces the image to half its original scale. To open this dialog, select View | Zoom | Out By X from the Viewer menu bar.

Reduction: Enter the reduction factor (not the zoom ratio). Resampling Method:

Select the Resampling method to apply to the top raster layer in the Viewer. All other layers zoomed in the Viewer will retain the resample method with which they were opened.

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To change only the resampling method, the reduction factor must be set to 1.00. Click on the popup list button to select the resampling method to use. The options are described below: Nearest Neighbor

Use the value of the closest pixel to assign to the output pixel value.

Bilinear Interpolation Use the data file values of four pixels in a 2 x 2 window to calculate an output value with a bilinear function. Cubic Convolution Use the data file values of 16 pixels in a 4 x 4 window to calculate an output value with a cubic function.

➲ Resampling is discussed in detail in the “Rectification” chapter of the ERDAS Field Guide. OK Click to start the process and close this dialog. Cancel Click to cancel this process and close this dialog. Help Click to open 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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Box Editor

Box Editor This dialog enables you to enter specific coordinates to position an Inquire Box or an annotation box that you are creating. Under UNIX this dialog is opened when you press the Space bar while the inquire box is opened or while you are drawing an annotation box. (Press the Space bar before or while dragging the mouse.) Under UINIX this dialog is also opened when you select Utility | Selector Properties... from the Viewer menu bar when there is an active inquire box or annotation box. As in all ERDAS IMAGINE dialogs, pressing the Tab key will move the cursor from field to field.

ULX: Edit the upper left X coordinate to position the selected element. ULY: Enter the upper left Y coordinate to position the selected element. LRX: Edit the lower right X coordinate to position the selected element. LRY: Edit the lower right Y coordinate to position the selected element. Selector Color: Right-hold on the popup list to select the Selector color. OK Click to use these coordinates and close this dialog. The box will be redrawn using the new coordinates. If this option was selected for a box that you are drawing, the new box will be selected.

Cancel Click to cancel this process and close this dialog. If this option was selected for a box that you are drawing, control will return to the mouse and you can continue to draw.

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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Ellipse Editor

Ellipse Editor This dialog enables you to modify the position and shape of an elliptical arc that is already created. This dialog is opened when you select an arc, click the Tools and Commands palette, and then press the Space bar.

icon in the Annotation

In this dialog, you can define the base, start, and end angles. Refer to the illustration below for an explanation of these angles. 90 Arc that is opened

end angle base angle

start angle

0

The base angle defines from where the start and end angles will be measured. In the illustration above, the thick red lines show a base angle of 0, and then what it would look like if the base angle were 90 (thin red lines). The start and end angles on the second drawing assume a base angle of 0.

X: Enter the X coordinate of the center of the ellipse that forms the arc. Y: Enter the Y coordinate of the center of the ellipse that forms the arc. W: Enter the width of the ellipse that forms the arc. H: Enter the height of the ellipse that forms the arc. Base Angle: Enter the base angle of the arc. Start Angle: Enter the start angle of the arc. End Angle: Enter the end angle of the arc. OK Click to use these parameters and close this dialog.

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Ellipse Editor

Cancel Click to cancel this process and close this dialog. Control will return to the mouse and you can continue to edit the arc manually.

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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Oval Editor

Oval Editor This dialog enables you to enter specific coordinates to position and size an oval that you are creating. This dialog is opened when you press the Space bar before or while you are drawing. (Select the oval tool and move your cursor into the Viewer and press the Space bar, or press the space bar while you are dragging to create the oval.)

Center X: Enter the center X coordinate of the oval. Center Y: Enter the center Y coordinate of the oval. Width: Enter the width of the oval. Height: Enter the height of the oval. OK Click to use these parameters to position the oval and close this dialog. The oval will be drawn in the Viewer.

Cancel Click to cancel this process and close this dialog. Control will return to the mouse and you can continue to manually draw the oval.

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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Point Edit

Point Edit This dialog enables you to enter specific coordinates to position an inquire cursor or an annotation point. Under UNIX this dialog is opened when you select the Point tool and move your cursor into the Viewer, then press the Space bar. Under UNIX this dialog is also opened when you select Utility | Selector Properties... from the Viewer menu bar when there is an active inquire cursor or annotation point.

X: Enter the X position of the point. Y: Enter the Y position of the point. Selector Color: Right-hold to select the Selector color. OK Click to use this coordinate and close this dialog. The Point displays in the Viewer. Cancel Click to cancel this process and close this dialog. Control will return to the mouse and you can click to place the Point at the desired location. 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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Poly Edit

Poly Edit This dialog enables you to enter specific coordinates to position and size a polygon or polyline that you are creating. This dialog is opened when you press the Space bar before or while you are drawing. (Select the polygon or polyline tool and move your cursor into the Viewer and press the Space bar, or press the Space bar while you are creating the polygon/polyline.) You may also select Pick Properties... from the Viewer Utility menu.

(CellArray) Any currently selected vertices of the polygon or polyline are displayed in a CellArray. Edit these or enter new vertices to create the polygon/polyline. Right-hold in the Row column for the Row Selection popup. Right-hold on any column heading for the Column Options popup.

OK Click to use these vertices to create the polygon/polyline. Cancel Click to cancel this process and close this dialog. Control will return to the mouse and you can continue to select vertices by clicking the desired points. 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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RotBox Editor

RotBox Editor This dialog enables you to specify the position, size, and rotation of the rotation boxes that open around selected annotation elements or open in raster images. This dialog is opened when you select an annotation element or open a rotation box in a raster image and (UNIX only) press the space bar with the cursor anywhere inside the Viewer. This dialog is also opened when you then (Windows only) select Utility | Selector Properties... from the Viewer menu bar.

X: Enter the X coordinate of the center of the rotation box. Y: Enter the Y coordinate of the center of the rotation box. W: Enter the width of the box. H: Enter the height of the box. Angle: Enter the angle the box is to be rotated. Positive and negative rotations can be done. The positive rotation is controlled by the current setting of the Positive Rotation Direction preference in the User Interface and Session category of the Preference Editor dialog.

Selector Color: Click and hold the color patch to select a color for the box. Selecting Other brings up the colorwheel. OK Click to apply these parameters to the rotation box and close this dialog. Cancel Click to cancel this process and close this dialog. Control will return to the mouse and you can continue to edit the rotation box manually.

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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Simple Arc Edit

Simple Arc Edit This dialog enables you to specify the position and size of an elliptical arc that you are creating. This dialog is opened when you press the Space bar before or while you are drawing an arc. For more arc editing options, draw the arc, then select it. Click icon in the Annotation Tools and Commands palette, then press the Space bar to bring up the Ellipse Editor dialog.

Center X: Enter the center X coordinate of the ellipse that forms the arc. Center Y: Enter the center Y coordinate of the ellipse that forms the arc. Axis 1: Enter the size of the horizontal axis. Axis 2: Enter the size of the vertical axis. OK Click to apply these parameters to the arc and close this dialog. Cancel Click to cancel this process and close this dialog. Control will return to the mouse and you can continue to edit the arc manually.

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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Choose Symbology

Choose Symbology This dialog allows you to select the symbology file to use when displaying vector data. It is opened when you click the Set button in the File Selector dialog.

☞ The Set button is enabled only if the Use Symbology check box is on. Vector Layer: Use this file name part to select the symbology file to use. The default file extension is .evs.

OK Click to use the selected 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 more information about using vector data in ERDAS IMAGINE, see the ERDAS IMAGINE Tour Guides manual.

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Symbol Editor

Symbol Editor The Symbol Editor enables you to modify an existing symbol. It opens when you click the View... button on the Custom tab of the Symbol Chooser dialog.

File Close Select this option to close the Symbol Editor.

Utility Inquire Cursor... Select this option to open the Inquire Cursor dialog and place a crosshair cursor over the image in the Viewer. Inquire Box... Select this option to open the Inquire Box Coordinates dialog and place a query box over the image in the Viewer. Inquire Color... Select this option to select the inquire cursor color. The Inquire Color dialog is opened. Inquire Shape... Select this option to change the shape of the cursor. The Inquire Shape dialog is opened. Inquire Home Select this option to move the cursor to the center of the displayed portion of the image.

View Zoom Select this option to reduce, magnify, and zoom in on a particular area. The zoom is based on the center of the displayed portion of the image. To zoom based on a user-selected portion of the image, use the Rotate and Magnify Area option, the right mouse button menu, or the zoom icons on the tool bar. In By 2 Select this option to quickly magnify the displayed data. Multiplies the current zoom ratio by 2. Out By 2 Select this option to quickly reduce the displayed data. Divides the current zoom ratio by 2. In By X... Select this option to specify a custom zoom. The Set Zoom Ratio dialog is opened. Out By X... Select this option to specify a custom reduction factor. The Reduction dialog is opened.

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Symbol Editor Default In the Viewer, left-hold to reset the zoom ratio to 1. Any annotation or vector data is reset to register with the raster layers. If annotation or vector is displayed with no raster layers, then the zoom ratio is reset to its original value when the data were displayed. Scale Image To Window Select this option to resize the image to the viewer size. Window To Image Select this option to resize the viewer to the image size. Background Color... Select this option to change the background color of the Viewer. The Background Color dialog is opened. Status Bar Turn on this check box to enable the single-line help which displays at the bottom of the Viewer window. Use the Preference Editor to set the default for this option. Scroll Bars This check box turns the Viewer scroll bars on or off. Turning off the scroll bars increases your display area. Use the Preference Editor to set the default for this option. Menu Bar This check box turns the Viewer menu bar on or off. Turning off the menu bar increases your display area. Use the Preference Editor to set the default for this option. Tool Bar Turn on this check box to enable the row of Viewer icon tools which displays at the top of the Viewer window. Use the Preference Editor to set the default for this option. Borders

This checkbox enables the Window Manager border.

Annotation Tools... Select this option to open the Annotation tools palette. Undo Select this option to undo the last edit. Select multiple times to undo a series of edits (back to the last saved version of this annotation layer). Cut Select this option to delete the selected element(s). A copy is kept in the copy/paste buffer. Copy Select this option to make a copy of the selected element(s) in the copy/paste buffer. Paste Select this option to paste the contents of the copy/paste buffer to the same location. Select the copied element and move it to the desired location. Group Select this option to combine the selected elements into a group element.

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Symbol Editor Ungroup Select this option to break a group element into single elements. Reshape Select this option to reshape a selected polygon, polyline, arc, or AOI. This option also lets you create or reshape the invisible polyline that text may follow:

♦ left-hold to move a vertex of the polygon, polyline or text polyline; ♦ middle-click to add a vertex to the polygon, polyline or text polyline; ♦ shift-middle-click to add or remove a vertex from the polygon, polyline or text polyline;

♦ left-hold on any side of a polygon or segment of a polyline or text polyline to move it without rotating. To quit reshape mode, Click outside the element or select another element. To enter precise size and positioning coordinates when reshaping an arc, press the space bar after clicking Reshape to bring up the Ellipse Editor dialog. Raise To the Front Click to move the selected element(s) in front of all others in the drawing order. Forward by One Click to move the selected element(s) forward by one rank in the drawing order. Lower To the Back Click to move the selected element(s) behind all others in the drawing order. Backward by One Click to move the selected element(s) back by one rank in the drawing order. Distribute Vertically Click to evenly distribute the centers of selected elements vertically between the top element and the bottom element. Horizontally Click to evenly distribute the centers of selected elements horizontally between the right element and the left element. Flip Vertically Click to flip selected annotation vertically.

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Symbol Editor Horizontally Click to flip selected annotation horizontally. Align Object North Select this option to align selected annotation toward north. Alignment... Select this option to align selected annotation objects. The Align dialog is opened. Element Properties... Click to open the Properties dialog for the selected element:

♦ Text ♦ Ellipse ♦ Arc ♦ Rectangle ♦ Polygon/Polyline ♦ Symbol ♦ Map frame ♦ Group Styles... Select this option to open the Annotation Styles dialog. Attributes...

Select this option to open the Annotation Attributes dialog.

Help Click to choose the following option: Help for Symbol Editor

Click to view the On-Line Help for the Symbol Editor.

Click to print the contents of the Viewer.

Click to reset the image to a zoom factor of 1.0.

Click to start/update the inquire cursor. The Inquire Cursor dialog is opened if it is not already open.

Click to display the tool palette for top layer.

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Symbol Editor

Click to reset the window tools.

Click to zoom out by 2. You must click in the Viewer to indicate the center of the reduced area.

Click to zoom out by 2. You must click in the Viewer to indicate the center of the reduced area.

Click to roam the image. Click and drag the hand-shaped cursor over the image to pan up, down, left, and right.

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Select Colors

Select Colors This dialog enables you to create/select lookup tables, or palettes, to use for the color scheme in the project file. This dialog opens when you select TerraModel | Palette... from the IMAGINE Viewer menu bar.

Palette Names: List of available palettes. Apply Click to apply the current palette to the color scheme in the project file. Save Click to save the current palette to the project file. Add... Click to add a palette. The Add Palette dialog opens. Create... Click to open a new palette. The New Palette dialog opens. Close Click to close this dialog. Help Click to view the On-Line Help for this dialog.

85

New Palette

New Palette This dialog enables you to create a new palette with a specified number of entries. When creating new palette files for displaying terramodel layers, create the files in the directory where IMAGINE was started or in the $IMAGINE_HOME/etc directory for the new palettes to be available the next time IMAGINE is started. Otherwise, use the Add option in the Palette editor to select palettes from other directories. This dialog opens when you click Create... in the Select Colors dialog.

Palette Name: Enter the palette name in the text entry field or select the palette name from the file list.

Count: Adjust the number of colors in the palette. OK Click to open the new palette. Cancel Click to cancel process of opening a new palette and close this dialog. Help Click to view the On-Line Help for this dialog.

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Add Palette

Add Palette This dialog enables you to add a new palette. This dialog is opened when you click Add... in the Select Colors dialog.

Palette Name: Enter the palette name you wish to add in the text field or select the palette name from the file list.

OK Click to open the added palette. Cancel Click to not add the palette and close this dialog. Help Click to view the On-Line Help for this dialog.

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Select Layers

Select Layers This dialog enables you to select which data layers from the project file to display in the Viewer. This dialog opens when you select TerraModel | Select Layer... from the IMAGINE Viewer menu bar. Layers selected for display are marked with an X in the “X” column. By default, all layers are initially displayed. To undisplay a data layer, click again in the “X” column.

Apply Click to open the selected data layers in the Viewer. All Select to display all data layers. None Select to undisplay all data layers. Close Click to close this dialog. Help Click to view the On-Line Help for this dialog.

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About the IMAGINE Viewer

About the IMAGINE Viewer The ERDAS IMAGINE Viewer is the “main window” for displaying raster, vector, and/or annotation data. You can open as many Viewer windows as your window manager supports. Many of the functions in ERDAS IMAGINE are available via the Viewer menu bar, across the top of the window, and the Quick View menu, which is displayed when you right-hold in a Viewer window. This documentation explains: Starting a Viewer Moving and Resizing the Window Scrolling (roaming) Zooming (magnification and reduction) Inquire Cursor Linking Viewer Windows Viewing Multiple Layers Another related topic is: Viewer vs. 7.X Display

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Starting a Viewer

Starting a Viewer A Viewer window will automatically open when you start ERDAS IMAGINE. To start another Viewer window, click this button on the IMAGINE icon panel:

You can also use any of the Split operations under the View menu of the Viewer window to start another Viewer. You can pre-set many options that affect how a new Viewer comes up by setting Viewer Preferences.

The Viewer Window The parts of the Viewer window are explained in the following illustration.

90

Starting a Viewer

The title bar shows the number of the Viewer, which is referred to in other operations.

Right click inside the viewer to pop up a Quick View menu of frequently used functions.

Left-hold on Viewer menu bar item for list of operations to perform on the displayed data. The tool bar consists of icons to provide rapid access to frequently used operations.

Information about the button under the cursor is displayed in this Status Bar. Children of the process report here also. Left-hold and drag any one of these corners to resize the Viewer.

Use the scroll bars to scroll the data. The size of the bar in the panel shows how much of the data area you are viewing now.

91

Starting a Viewer

Opening Data Layers To is opened a layer of data in a Viewer, you “open” that layer file. Under the File menu on the Viewer menu bar, select Open and then click on the kind of layer that you want to view. A File Selector dialog is opened.

Changing the Viewer Window The Viewer window can be moved or resized like any other window under your window manager. Although window managers vary, these methods will generally work: To move a Viewer...

Left-hold on the border or title of the Viewer and drag to the new location.

To resize a Viewer...

Left-hold, and then drag any corner or side. The displayed image will refresh in the resized window.

Resampling Resampling is used to calculate pixel values when one raster grid must be fitted to another. When a raster image is opened, the raster grid defined by the file must be fit to the grid of screen pixels in the Viewer. All Viewer operations are file-based. So, any time you resample in the Viewer, the Viewer uses the file as its source. If you zoom the raster layer, the Viewer resamples the file grid to the new screen grid. The resampling methods available are:

♦ Nearest Neighbor - uses the value of the closest pixel to assign to the output pixel value. ♦ Bilinear Interpolation - uses the data file values of four pixels in a 2 x 2 window to calculate an output value with a bilinear function.

♦ Cubic Convolution - uses the data file values of 16 pixels in a 4 x 4 window to calculate an output value with a cubic function.

➲ These are discussed in detail in the ERDAS Field Guide. The default resampling method is Nearest Neighbor.

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Scrolling

Scrolling All formats of data (raster, vector, annotation) will scroll in the Viewer. The Viewer window represents a window into whatever data set is displayed. Since most data sets exceed the displayable area of a window, the Viewer provides the ability to scroll the window to different parts of the data set. You can also scroll with linked Viewers. You can scroll with the scroll bars that appear at the right side and at the bottom of the Viewer window. As with other Motif-style windows, the scroll bars represent the amount of the file that opens in the window as a proportion of the length of the scroll bar panel. To go directly to another part of the image...

Left-hold a scroll bar and drag it to another location on the panel. The image will refresh when you let go.

To scroll by a block of 64 screen pixels...

Click in the scroll bar. The data will scroll towards your click.

To scroll all the way in any direction...

Control-click the appropriate arrow in the scroll bar panel.

To scroll slowly in any direction...

Click on an arrow at either end of the scroll bars.

To scroll by 1 screen pixel...

Click on an arrow at either end of the scroll bars.

You can also scroll to other parts of the image using the roam (hand) tool on the Viewer tool bar.

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Zooming

Zooming Zooming is the magnification or reduction of an image in the Viewer. Zooming has no effect on how the image is stored in a file. To provide maximum convenience and accuracy, there are several methods of zooming. The quickest and simplest are the zoom-by-2 options. These are accessible from the Viewer toolbar. The quick zoom buttons, and , enlarge and reduce the image without changing the center of the viewable area. These options are repeated in the View menu. The re-centering zoom tools, and , enlarge and reduce the image and also shift the image so that the clicked spot is in the center of the Viewer. There are also options on the View | Zoom submenu ( In By X ... and Out By X ... ) that allow you to specify the exact zoom ratio (1.37 for example) and to specify or change the resample method.

Animated Zoom When Animated Zoom is enabled and you use a zoom tool or button, the content of the Viewer is zoomed in or out in a series of steps that simulate animation. The displayed image then resampled. This is the default zoom behavior. Animated zoom may be suspended by unsetting the Enable Animated Zoom preference in the Viewer category of the Preference Editor.

Box Zoom When Box Zoom is enabled and either of the Zoom Re-center tools (

or

) is selected,

you can drag a box in the Viewer to specify the zoomed area. For example, when the tool is selected, you can drag a box around an area within the Viewer and when the mouse button is released, that area will be magnified so that the surounded area fits entirely within the Viewer. When the tool is selected and a box is dragged, the entire Viewer area is reduced so that it will fit completely within the bounding box. The Viewer is then populated with surrounding imagery if any. Box zoom may be disabled by unsetting the Enable Box Zoom preference in the Viewer category of the Preference Editor

94

Zooming

Real-Time Zoom When either of the Zoom Re-center tools ( or ) is selected, you can hold the middle mouse button (or Control key and left mouse button) and move the mouse forward and backward to zoom in and out in real time. There is no preference for this feature.

Zoom Ratio The zoom ratio describes the size of the image on the screen in terms of the number of file pixels used to store the image. It is the ratio of the number of screen pixels in the X or Y dimension to the number that are used to display the corresponding file pixels. A zoom ratio greater than 1 is a magnification, which makes the image larger in the Viewer. A zoom ratio less than 1 is a reduction, which makes the image smaller in the Viewer. A zoom ratio of 1 means...

each file pixel is displayed with 1 screen pixel in the Viewer.

A zoom ratio of 2 means...

each file pixel is displayed with a block of 2 × 2 screen pixels. Effectively, the image is displayed at 200%.

A zoom ratio of 0.5 means...

each block of 2 × 2 file pixels is displayed with 1 screen pixel. Effectively, the image is displayed at 50%.

ERDAS IMAGINE allows floating point zoom ratios, so that images can be zoomed at virtually any scale. Resampling is necessary whenever an image is displayed with a new pixel grid. The resampling method used when an image is zoomed is the same one used when the image is displayed, as specified in the File Selector dialog. The default resampling method is Nearest Neighbor. The resample method is changed by using the Set Zoom Ratio dialog. Whenever you change the zoom ratio, the scroll bars and pointers automatically reset to reflect the new display. The center of the new view depends upon which zoom method is used.

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Viewing Multiple Layers

Viewing Multiple Layers You can view as many layers of all types (raster, vector, annotation) as you like at one time in a single Viewer. (Be sure to turn off the Clear Display check box when you open subsequent layers.) Multiple layers in one Viewer must all be referenced to the same map coordinate system. The layers are positioned geographically within the window, and resampled to the same scale as previously displayed layers. Therefore, raster layers in one Viewer can have different cell sizes. When you magnify or reduce multiple layers, raster layers are resampled from the file to fit to the new scale.

Overlapping Layers When layers overlap, the order in which you open the layers is very important. The last layer that you open will always appear to be “on top” of the previously opened layers. In a raster layer or layerset, values of zero are transparent in the Viewer, meaning that they have no opacity. So, if you open a raster layer with zeros over other layers, the areas with zero values will allow the underlying layers to show through. Use the Arrange Layers dialog to re-stack layers in a Viewer so that they overlap in different order, if needed. Use the Color Chooser dialog to change the opacity of raster data.

Non-Overlapping Layers Multiple layers that are opened in the same Viewer do not have to overlap. You can open layers in the same Viewer that cover distinct geographic areas. The layers will be positioned in the Viewer window according to their map coordinates, and will be positioned relative to one another geographically.

96

Quick View Menu

Quick View Menu The Quick View menu appears whenever you right-hold in the display area of a Viewer or Map Composer window. Functions include geographical linking, zooming (magnification and reduction), using pointers for pixel inquiry, and Viewer/Map Composer window sizing. For more information, read the On-Line Help about the IMAGINE Viewer.

Inquire Cursor... This option starts an Inquire Cursor. The Inquire Cursor dialog is opened.

Inquire Box... This option starts an Inquire Box. The Inquire Box Coordinates dialog is opened.

Zoom Right-hold for options that control the zoom ratio of the data that are currently displayed in the Viewer. Zoom In By 2 by 2. Zoom Out By 2 by 2.

Quickly magnify the displayed data. The current zoom ratio is multiplied Quickly reduce the displayed data. The current zoom ratio is divided

Default Zoom In the Viewer, reset the zoom ratio to 1. Any annotation data are reset to register with the raster layers. If annotation is displayed with no raster layers, then the zoom ratio is reset to its original value when the data were displayed. In the Map Composer, zoom ratio is set to “actual size,” as it would appear when printed. Rotate and Magnify Area A rotation box (RotBox) is opened in the Viewer. The box’s position is displayed in the status bar at the bottom of the Viewer dialog. -- to move and position the box, left-hold the mouse in the box and drag the box to the desired location. -- to resize the box, left-hold and drag the filled-circle handles on the corners and sides of the box. -- to rotate the box, middle-hold inside the box and drag in the direction you want to rotate and magnify. You can also modify the position and rotation angle of the box by using the RotBox Editor dialog. This dialog is opened by pressing the space bar with the cursor anywhere inside the Viewer.

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Quick View Menu When you have the box positioned the way you want it, double-left-click inside the box and the area will be magnified. Create Magnifier Start a new Viewer with the same data displayed at a zoom ratio of 4 × the zoom ratio in the Viewer. The magnifying ratio can be increased or decreased by decreasing or increasing the size of the magnifying box in the Viewer. This option is not available in a Map Composer Viewer window. The magnifier Viewer is closed by right-holding in the Viewer title bar and selecting from the Window list.

Toggle Window This option lets you change a resized Viewer back to the previous size. Fit Image To Window Fit Map To Window Set the zoom ratio so that the displayed data fit as closely as possible into the current Viewer. The aspect ratio of the data is always maintained, such that the longest dimension of the data is refitted to the corresponding Viewer window dimension.

Fit Window To Image Fit Window To Map Resize the Viewer window to fit the image (unless the data are larger than the monitor screen).

Geo. Link/Unlink... Link/Unlink... Use this option to geographically link or unlink Viewer windows. The Link/Unlink Instructions appear. A geographic link will not reflect changes in the arrangement of layers, band combinations, or changes by other tools in the Viewer. From the Viewer menu bar, select View | Link/Unlink Viewers | Spectral to perform spectral linking. This option is not available from a Map Composer viewer.

Background Color... Right-hold to set the background color of the Viewer. The Background Color dialog is opened.

Close Window Right-hold to close the Viewer. Status Bar Turn on this check box to enable the single-line help which displays at the bottom of the Viewer. Turning off the status bar increases your display area. Use the Viewer category of the Preference Editor to set the default for this option.

98

Quick View Menu

Scroll Bars This check box turns the Viewer scroll bars on or off. Turning off the scroll bars increases your display area. Use the Viewer category of the Preference Editor to set the default for this option.

Menu Bar This check box turns the Viewer menu bar on or off. Turning off the menu bar increases your display area. Use the Viewer category of the Preference Editor to set the default for this option.

Tool Bar Turn on this check box to enable the row of Viewer icon tools which displays at the top of the Viewer. Use the Viewer category of the Preference Editor to set the default for this option.

Borders This check box turns the Viewer borders on or off. Use the Viewer category of the Preference Editor to set the default for this option.

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

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Inquiry Functions

Inquiry Functions ERDAS IMAGINE shows you information about opened data through the Inquiry functions. Inquiry functions can be accessed any of these ways:

♦ through the Quick View right-button menu ♦ from the Utility menu on the Viewer menu bar ♦ by left-clicking the

icon on the Viewer tool bar

Pointers are the tools that you use to examine the data pixel by pixel, and to define areas of an image in a Viewer. Pointers are positioned according to the pixels in the data. If you change the zoom ratio, scroll the data, or warp it in the Viewer, the pointers will stay on the same pixels and in the same geographic location on the data. When you use a pointer, a dialog is opened showing you the coordinates of the pointer. You can use the dialog to move the pointer, or you can left-hold the pointer and move it to the desired location. You can use these types of pointers:

♦ the inquire cursor (cross hair), which brings up the Inquire Cursor dialog, or ♦ the inquire box, which brings up the Inquire Box Coordinates dialog. It is often useful to use pointers in linked Viewers.

100

Inquiry Functions

Active Pointers One pointer at a time can be active in a Viewer. An active pointer has solid lines. An inactive pointer has dashed lines. A pointer becomes active when you left-click on it (cross hairs) or inside it (box). If boxes overlap, you can left-click multiple times until the desired box is active.

Moving an Inquire Cursor To move an inquire cursor (cross hairs), do any of the following:

♦ left-hold the intersection of the cross hairs and drag it to the desired location, ♦ enter the desired coordinates in the Inquire Cursor dialog, or ♦ use the 4 arrow icons in the Inquire Cursor dialog to move the cursor by map or file units in any direction. When you left-click the Close button in the Inquire Cursor dialog, the cursor is also dismissed. Zooming or Warping the Data If you change the zoom ratio or linear adjustment (scale, offset, rotation, reflection) of the data, the Viewer will redisplay so that the inquire cursor is in the center of the Viewer (or as close as possible). This occurs even if the inquire cursor is not active when the Viewer redisplays.

Moving and Resizing an Inquire Box To move an inquire, you can left-hold on the inside of the and drag it to the desired location. To move and/or resize the, do any of the following:

♦ left-hold the corner of the and drag that corner to the desired location, ♦ left-hold the side of the and drag that side to the desired location, or ♦ enter the desired coordinates of the upper left and/or lower right corners in the Inquire Box Coordinates dialog and left-click Apply. When you left-click the Close button in the Inquire Box Coordinates dialog, the box is also dismissed. Zooming or Warping the Data If you change the zoom ratio or linear adjustment (scale, offset, rotation, reflection) of the data, the upper left and lower right corners of the inquire box will stay in the same geographic location.

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Inquiry Functions If the data are rotated, this will cause the aspect ratio of the and the geographic locations of the other corners to change.

Linking Viewers Linking is appropriate when two Viewers cover the same geographic area (at least partially) and are referenced to the same map units. When two Viewers are linked:

♦ either the same geographic point is opened in the centers of both Viewers, or a link box shows where one view fits inside the other

♦ scrolling one Viewer affects the other ♦ you can manipulate the zoom ratio of one Viewer from another ♦ any inquire cursors in one Viewer appear in the other, for multi-Viewer pixel inquiry It is often helpful to open a wide view of a scene in one Viewer, and then a close-up of a particular area in another Viewer. When two such Viewers are linked, a link box appears in the wide view window to show where the close-up view lies. When the data in two linked Viewers are at the same scale, scrolling in one window causes scrolling in the other, so that they both display the same area.

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Inquiry Functions

If one view fits inside the other in linked Viewers, a link box shows the extent of the larger-scale view.

Making a Link You can link a series of Viewers in a chain, or link several Viewers to a common Viewer. However you do it, Viewers are always linked two at a time. If several Viewers are linked to a common Viewer, there will be multiple boxes in that Viewer.

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Image Display

Image Display This document explains the task of displaying raster data in the Viewer, and defines some important terms that are relevant to displaying raster data.

➲ See the “Image Display” chapter in the ERDAS Field Guide for more information on displaying raster data.

Screen Pixels Just as a pixel in a file represents the smallest element of data in the file, a pixel on a color monitor is the smallest unit of display. To differentiate between the two, we call them file pixels and screen pixels. When you open a raster layer to display raster data in a Viewer, by default, each pixel in the layer will display in the Viewer as one screen pixel. But in many cases, you will want to zoom your image in the Viewer, so that the image is larger or smaller on the screen. When you magnify or reduce, one file pixel no longer corresponds to one screen pixel. For example, if an image is displayed with a magnification of 2, then one file pixel will take up 4 (2 x 2) screen pixels on the display screen. To is opened an image, the value or values that make up a file pixel must be transformed into a screen pixel, which has properties that can be seen and visually interpreted. Each screen pixel is given a color that is meaningful and relevant to the values of the file pixel(s) that it represents. The result is an image that can be interpreted with the human eye.

Primary Colors Human perception of color comes from the relative amounts of red, green, and blue light that are measured by the sensors in the eye. These three colors combined produce a wide variety of colors—more than can be formed from the combinations of any other three colors. Red, green, and blue are therefore referred to as the primary colors. A nearly infinite number of shades can be produced when red, green, and blue light are combined. On a computer screen, different combinations of red, green, and blue light allow you to perceive changes across an image as variations in color. Color display devices that are available today yield 224, or 16,777,216 combinations of red, green, and blue.

Color Guns On a color monitor, color guns direct electron beams that fall on red, green, and blue phosphors. The phosphors glow at certain frequencies, resulting in different intensities of each primary color. Color monitors are often called RGB monitors, referring to the primary colors.

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Image Display Each screen pixel is represented by an equal number of red, green, and blue phosphors. The phosphors on the picture tube appear as tiny colored dots on the screen. The human eye integrates these dots together, and colors are perceived.

Brightness Values Brightness values (or screen values) are the quantities of each primary color to be output to each screen pixel. When an image is displayed, brightness values are calculated for all three color guns, for every pixel. All of the colors that can be output to the Viewer can be expressed with three brightness values— one for each color gun. Brightness values are in the range of 0 to 255, with 0 being no color, and 255 being the brightest color.

Bits for Display A bit is a binary digit, meaning a number that can have two possible values—0 and 1, or “off” and “on.” A set of bits, however, can have many more values, depending upon the number of bits used. The number of values that can be expressed by a set of bits is 2 to the power of the number of bits used. For example, the number of values that can be expressed by 3 bits is 8 (23 = 8). Displays are referred to in terms of a number of bits, such as 8-bit or 24-bit. These bits are used to determine the number of possible brightness values. For example, in a 24-bit display, 24 bits per pixel breaks down to eight bits for each of the three color guns per pixel. The number of possible values that can be expressed by eight bits is 28, or 256. Therefore, on a 24-bit display, each color gun of a pixel can have any one of 256 possible brightness values, expressed by the range of values 0 to 255. The combinations of the three color guns, each with 256 possible brightness values, yields 2563 , (or 224 , for the 24-bit image display), or 16,777,216 possible colors for each pixel on a 24-bit display.

Colormaps and Lookup Tables A color on the screen is created by a combination of red, green, and blue, where each of these components is represented as an 8-bit value. Therefore, 24 bits are needed to represent a color. Since many systems have only an 8-bit display, a colormap is used to translate the 8-bit value into a color. A colormap is an ordered set of colorcells, which is used to perform a function on a set of input values. To display or print an image, the colormap translates data file values in memory into brightness values for each color gun. Colormaps are not limited to 8-bit displays.

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Image Display Colormap vs. Lookup Table The colormap is a function of the is opened hardware, whereas a lookup table is a function of ERDAS IMAGINE. When you perform a contrast adjustment on an image in IMAGINE, you are using lookup tables. However, if you are using the auto-update function to view the adjustments in near real-time, then the colormap is being used to map the image through the lookup table. This process allows the colors on the screen to be updated in near real-time. ERDAS IMAGINE and Lookup Tables It is rare that the file values that are stored in a raster layer can be used as brightness values.

♦ In image files of interval or ratio data such as remotely-sensed data, the file values are often low and too close together to create an image with discernible contrast.

♦ In image files of nominal or ordinal data, the file values do not relate to brightness or color, but to a class number. The transformation of file values into brightness values in IMAGINE takes place with the use of lookup tables. A lookup table is an ordered set of numbers, which is used to perform a function on a set of input values. To display or print an image, lookup tables translate file values into brightness values. For example, the following lookup table translates numbers from the range 30 to 40 to the range 0 to 255: 30

>>

0

31

>>

25

32

>>

51

33

>>

76

34

>>

102

35

>>

127

36

>>

153

37

>>

178

38

>>

204

39

>>

229

40

>>

255

Three lookup tables are used in IMAGINE — one for each color gun. The source and function of the lookup tables depend upon the type of image that is being displayed.

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Image Display

♦ In true color and gray scale images, lookup tables are viewed and edited using contrast adjustment.

♦ In pseudo color images, lookup tables are stored as a color scheme.

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IMAGINE Viewer vs. ERDAS Ver. 7.X Display

IMAGINE Viewer vs. ERDAS Ver. 7.X Display If you are an ERDAS Ver. 7.X user and are familiar with the way that raster data are displayed with Ver. 7.X, then it is important to understand the differences between the ERDAS Ver. 7.X display and the ERDAS IMAGINE Viewer. The greatest difference between the two is that:

♦ ERDAS Ver. 7.X is display based — it stores data values and lookup tables in the display hardware and changes the function memory to manipulate the display.

♦ IMAGINE’s Viewer is file based — it continually manages lookup tables for all data that are being displayed and directly maps the file values through these tables to the screen. Other differences are outlined in the table below. Feature

ERDAS IMAGINE

ERDAS Ver. 7.X

Software continually manages color lookup tables.

Yes — all changes to display affect Viewer’s lookup tables.

No — LUTs stored to function memory and managed by separate programs.

Use of additional display hardware (e.g., RasterOpts) is transparent to user.

Yes — the Viewer manages all display hardware.

No — a separate display driver is needed for each display.

Virtual scrolling, zooming built in.

Yes — scrolling and zooming are managed by the Viewer.

No — managed by programs or by display driver.

Multiple is opened without additional hardware.

Yes — as many Viewer windows as desired on multiple screens.

Sometimes — multiple display drivers can be run on some UNIX platforms (e.g., SunView).

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IMAGINE Viewer vs. ERDAS Ver. 7.X Display

Feature

ERDAS IMAGINE

ERDAS Ver. 7.X

Multiple layers in one view possible

Yes — non-raster data (annotation, vectors) are displayed same as raster, with optional use of opacity to mix the layers.

No — limited to one RGB image plane and one overlay plane.

Multiple layers can be any cell size and cover different areas

Yes — multiple layers are georeferenced in the Viewer, even if they have different cell sizes or do not overlap.

No — data in same view must have same cell size and cover same area.

Opacity supported

Yes — zero values are transparent (0% opacity). Opacity can be controlled for each file value in a layer.

Limited — only overlay plane zero values are transparent (0% opacity).

Handles class wrap-around on categorical files

Yes — Viewer manages many classes by compressing colors, or by wraparound, depending on how you set up the color table.

No — no system in display driver for handling more classes than display colors.

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Gray Scale Images

Gray Scale Images Gray scale images are like true color images in every regard except that there is only one lookup table instead of three. In gray scale, the file values in the layer are mapped through one lookup table that is applied equally to all three color guns, which results in shades of gray. Gray scale mapping is appropriate for continuous data in a single layer. You might use gray scale to analyze single layers in a layerset.

Gray Scale Lookup Tables As in true color images, the lookup table for a gray scale image is calculated using the mean and 2 standard deviations of the file values in the layer.

➲ See the ERDAS Field Guide for a complete description of this process. You can change this lookup table using the Brightness/Contrast Tool or the Gray Lookup Table dialog. You can also use the Data Stretch option in the File Selector dialog.

Gray Scale Lookup Tables Raster Layer

Gray LUT

Gray Scale image in Viewer

Contrast Stretch and Statistics The contrast stretch for gray scale mapping and the ways that the statistics of the data are used are the same as for true color mapping.

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Pseudo Color Images

Pseudo Color Images Generally, categorical data have either been classified (meaning that the file pixels have been put into distinct categories according to their values) or digitized from maps or other data layers. In either case, each image file value is a class value, which is simply a number for a particular category. Since sequential class values are not necessarily related, the simple gradations that are possible in true color or gray scale images are not usually useful in pseudo color. The class system gives the pseudo color image a “paint-by-number” look, in which each class can have its own color.

➲ See the “Image Display” chapter in the ERDAS Field Guide for information about PseudoColor displays.

Lookup Tables For pseudo color images, the lookup tables are used in IMAGINE to assign colors to the classes. Each class value is mapped through all three lookup tables to obtain three brightness values, one for each color gun.

Color Schemes A color scheme is a pseudo color lookup table. Like a true color lookup table, it converts file values (in this case, class values) to output brightness values. In pseudo color, though, the color for each input file value is controlled separately and distinctly. You can explicitly assign colors to each class value in the layer that is displayed.

Pseudo Color Lookup Tables Red LUT Raster Layer

Green LUT Blue LUT

Pseudo Color image in Viewer

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Pseudo Color Images Gray Scale Color Scheme A gray scale color scheme is a pseudo color lookup table that is composed completely of shades of gray. When a gray scale color scheme is applied automatically, it generally consists of a gradation ranging from black to white. This could also be called a gray level slice. A gray scale color scheme for categorical data should not be confused with gray scale mapping of continuous data.

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True Color Images

True Color Images Since the file values in continuous data are quantitative and related, the brightness values of a true color image are also quantitative and related. The screen pixels represent the relationships between the values of the file pixels by their colors. For example, a screen pixel that is bright red has a high brightness value in the red color gun, and a high file value in the layer assigned to red, relative to other file values in that layer. A set of layers that is opened with true color mapping is called a layerset.

➲ See the “Image Display” chapter in the ERDAS Field Guide for information on TrueColor displays.

True Color Lookup Tables To is opened the layers independently, there is a separate lookup table for each layer.

♦ The lookup tables can be viewed and edited with the Contrast/Brightness Tool and the Breakpoint Editor dialog.

♦ If the image is being opened for the first time, a contrast stretch is performed based on 2 standard deviations from the mean of the input file values (± 2σ) . ➲ See the ERDAS Field Guide for information about the ± 2σ contrast stretch. The file values in each opened layer are mapped through the corresponding lookup tables to output the brightness values used in the Viewer. True Color Lookup Tables Layer to Red Layer to Green Layer to Blue

Red LUT Green LUT Blue LUT

True Color (RGB) image in Viewer

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True Color Images Statistics for Contrast Stretch If a contrast stretch is used to is opened the data, certain statistics are necessary, such as the mean and the standard deviation of the file values in each layer. These statistics are stored along with the raster data in the .img file. Whenever a new file is generated or imported, statistics are calculated for each layer. These statistics can be viewed or recalculated using the Image Info dialog.

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True Color Images

Layer to Color Gun Assignments Usually, a three-layer set of raster layers is opened in true color (there may be more layers in the file). These three layers correspond to the three color guns — red, green, and blue. The most useful color assignments are those that allow you to interpret the opened image easily. For example:

♦ a natural-color simulated image will approximate the colors that would appear to a human observer of the scene.

♦ a color-infrared simulated image shows the scene as it would appear on color infrared film, which is familiar to many analysts. Layer assignments are expressed in R,G,B order. For example, the assignment 4,2,1 means that layer 4 is assigned to red, layer 2 to green, and layer 1 to blue. This is the default assignment used when a 4-layer set is opened with the Viewer. Below are some widely used layer to color gun assignments.

♦ Landsat MSS - 4,2,1 ♦ Landsat TM - natural color: 3,2,1 ♦ Landsat TM - color infrared: 4,3,2 ♦ SPOT Multispectral - color infrared: 3,2,1

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