Turbo Squid: 3D Models, Plugins, Textures, and more. The NGS Geodetic Tool Kit. TerrainMap.com. Digital Elevation Modeling and Mapping Digital Elevation Model. The most basic and interesting geographical data type is the digital elevation model (DEM).
A Digital Elevation Model is an ASCII or binary file that contains only spatial elevation data in a regular gridded pattern in raster format. The traditional source for United States DEM data has been the USGS Geographic Data Download .