Digital Elevation Model (DEM)

"A representation of the topography of the Earth in digital format, that is, by coordinates and numerical descriptions of altitude." (National Aeronautics and Space Administration, 2017)

Examples for open source DEMs are Space Shuttle Radar Topography Mission (SRTM), ASTER Global Digital Elevation Model, JAXA’s Global ALOS 3D World (, 2018)


"Glossary". Earth Observatory, National Aeronautics and Space Administration. Last modified August 4, 2017.
Accessed February 14, 2019.
“5 Free Global DEM Data Sources – Digital Elevation Models”. GISGeography, Last modified February 21, 2018.
Accessed April 1, 2019.

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ARSET - River Basin Delineation Based on NASA Digital Elevation Data


River basins (known as watersheds in North America) are areas of land that drain precipitation, surface water, and underlying groundwater into a river and its tributaries, eventually reaching a common outlet such as a lake, reservoir, river, or estuary. The drainage pattern is from smaller sub-basin to larger sub-basin, and from higher elevation to lower elevation. Land surface processes, precipitation, storm water, and wastewater runoff within basins have substantial impact on quantity and quality of the water draining into tributaries.