DEM

DEM stands for digital elevation model.  It is a form of remote sensing that allows  us to visualize the elevation of land.  This DEM image is of some mountains in California.  We can very easily see where the peaks and valleys are in this mountain range.  You can also tell which mountains are higher in elevation with DEM.http://www.humboldt.edu/geology/courses/geology350/350_maps_airphotos.html