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 (GISGeography.com, 2018)

Sources

"Glossary". Earth Observatory, National Aeronautics and Space Administration. Last modified August 4, 2017.
https://www.earthobservatory.nasa.gov/glossary/all.
Accessed February 14, 2019.
“5 Free Global DEM Data Sources – Digital Elevation Models”. GISGeography, GISGeography.com. Last modified February 21, 2018.
https://gisgeography.com/free-global-dem-data-sources/.
Accessed April 1, 2019.