Chapter 9b

Chapter 9Digital Terrain Modeling

Figure 9.13

Mesh Simplification ► The

process by which a TIN model is constructed from DEM data.

► It

has been shown that the number of elevation points in DEMs obtained from the USGS may be reduced significantly (to less than 5%) in TINs with only a very minor decrease in quality.

Surface Representation and Analysis ► Digital

Terrain Modeling may be used to answer a variety of spatial questions by employing one or more of the following classes of analytical techniques:   

Interpolation and Surface Fitting Creating New DEM data sets Extraction of Topographic Attributes and Landscape Features

Figure 9.18

Figure 9.19

What you don’t already know about Interpolation ► Local

and global algorithms

► Trend

surface analysis

► Kriging

and its glory-its an optimum interpolation method that incorporates   

Attribute values Spatial Autocorrelation Directional Trends

Figure 9.16

Figure 9.17

Extraction of Topographic Attributes and Landscape Features

► Primary

       

Attributes one can extract:

Elevation Slope Aspect Catchment Area Flow Path Flow Accumulation Profile Curvature: curvature of slope Plan Curvature: contour curvature

Figure 9.20

Figure 9.21