Terrain simulation of United States Geological Survey Digital Elevation Models

This thesis deals with the presentation of digital terrain in a three dimensional surface representation. The data base consists of digital spatial coordinate elevational data for terrain information based on the U.S. Geological Survey (USGS) Digital Elevation Models (OEM). Processing was accomplished on a VAX 11/780 with display on a Vectrix VX384. The analysis approach uses bicubic patch methods (surface equations) to depict aspect, slope, light source and viewer perspective. The points on each patch are projected to the respective pixels on the display device and the z-depth of each pixel is stored in a screen-buffer. Closer points take precedence over more distance points, thus producing a realistic scene from the digital data. Application examples include simulation scenes of selected flood levels and stereo pair generation.