ABSTRACT
A digital elevation model (DEM) is a representation of terrain elevation as a function of geographic location. DEMs are typically represented in two formats: contour maps, where the surface is represented by lines of constant elevation at even intervals; or point heights, where the elevation surface is sampled on either a regular or irregular basis (Raaflaub and Collins, 2006). Elevation is a distinctive variable in GIS, because it is not only a simple, inexpensive, and intensively sampled variable, but also the most crucial and probably the most fundamental of all the variables (Atkinson, 2002). DEMs are playing an increasingly important role in the area of remote sensing image-based data capture, especially with the development of high spatial resolution satellite images (Zhu et al., 2005). DEM has become an indispensable quantitative environmental variable in most of the research topics of remote sensing (San and Suezen, 2005). DEM is now commonly used for rectifying satellite images, and the accuracy of these images is highly dependent on the accuracy of the DEM.
