This program is a simple terrain viewer, which reads USGS DEM files in ASCII format, and then renders actual Earth terrain with precision, which is selectable. Requires OpenGL support, in hardware highly recommended. Needs lots of CPU power and video memory . The key in this program is not a fancly look, but geometrically and optically correct rendering of Earth terrain to generate realistic view. Free for non-commercial use. Basic knowledge of geometry or GIS may be helpful to use this program.