Digital Elevation Model

A digital elevation model (DEM) is an image consisting of heights above sea level for a certain location. It shows terrain, viz. mountains, valleys and plains.

DEMs can be used in many ways, e.g. for the terrain correction of SAR images, hydrology or line-of-sight planning for radio towers. In SAR interferometry, these DEMs are often the final result.

The DEM on the right side shows a small mountain range just south of Delta Junction, Alaska. The data comes from the United States Geological Survey (USGS). The heights of about 400 meters above sea level were mapped to black, and heights of about 1800 meters above sea level to white.