Digital Elevation Model (also known as DEM, DTM, Digital Terrain Model). A digital representation of the elevation of locations on the land surface. A DEM is often used in reference to a set of elevation values representing the elvation at points [or pixels] in a rectangular grid on the Earth’s surface."
Source: McDonnell, Rachael and Karen Kemp. International GIS Dictionary. Geoinformation International, 1995.
GIS software, such as ArcGIS, can be used to manipulate DEMs, such as generating contour lines at the elevation interval of choice. With the ArcScene component of ArcGIS, DEMs can be displayed in 3D.
- Digital Elevation Model, DMTI. Extracted from the National Topographic Database 1:50,000. Resolution: 30 metres and 90 metres.
- SRTM30 and SRTM90. Shuttle Radar Topography Mission data of the United States. Resolution: 1 arc-seconds (approx. 30 meters) and 3 arc-seconds (approx. 90 meters).
- STRM90 SRTM 90 Digital Elevation Data, distributed in 5 degree by 5 degree tiles. Resolution: 3 arc-seconds (approx. 90 metres).
- GTOPO30. Global digital elevation model (DEM). Resolution: 30 arc seconds (approximately 1 kilometer)
- ETOPO2. Global elevation model that includes land and ocean floor topography. Resolution: 2 minutes (approximately 3.7 kilometers).
- Esri Data & Maps. SRTM 90, GTOPO30, and ETOPO2 data on DVD. SRTM 90 data divided by continent.
