DEM

http://eros.usgs.gov/#/Find_Data/Products_and_Data_Available/DEMs

A DEM  is a 3d map of the terrain of an area using data obtained by LIDAR, Doppler radar etc.. This map conveys the land around Sturgis, South Dakota. This map is considered a DEM because of its use of GIS technology to obtain data that was formed together to make a 3d image.