Digital elevation modeling Topography

relief map: sierra nevada mountains, spain



3d rendering of dem used topography of mars

the digital elevation model (dem) raster-based digital dataset of topography (hypsometry and/or bathymetry) of or part of earth (or telluric planet). pixels of dataset each assigned elevation value, , header portion of dataset defines area of coverage, units each pixel covers, , units of elevation (and zero-point). dems may derived existing paper maps , survey data, or may generated new satellite or other remotely sensed radar or sonar data.