Editing Digital elevation model (section)

{{Short description|3D computer-generated imagery and measurements of terrain}}
[[File:Mtm-05277e 3d.png|thumb|upright=1.3|[[3D computer graphics|3D rendering]] of a DTM of [[Tithonium Chasma]] on [[Mars]]]]

A '''digital elevation model''' ('''DEM''') or '''digital surface model''' ('''DSM''') is a [[3D computer graphics]] representation of [[elevation]] data to represent [[terrain]] or overlaying objects, commonly of a [[planet]], [[Natural satellite|moon]], or [[asteroid]]. A "global DEM" refers to a  [[discrete global grid]]. DEMs are used often in [[geographic information system]]s (GIS), and are the most common basis for digitally produced [[Relief mapping (computer graphics)|relief map]]s. 
A '''digital terrain model''' ('''DTM''') represents specifically the ground surface while DEM and DSM may represent tree top [[Canopy (biology)|canopy]] or [[building]] roofs.

While a DSM may be useful for [[Landscape planning|landscape modeling]], [[Urban planning|city modeling]] and visualization applications, a DTM is often required for flood or drainage modeling, [[Land-use planning|land-use studies]],<ref>[http://www.racurs.ru/www_download/articles/Balenovic.pdf I. Balenovic, H. Marjanovic, D. Vuletic, etc. Quality assessment of high density digital surface model over different land cover classes. PERIODICUM BIOLOGORUM. VOL. 117, No 4, 459–470, 2015.]</ref> geological applications, and other applications,<ref>{{cite book |chapter=Appendix A – Glossary and Acronyms |title=Severn Tidal Tributaries Catchment Flood Management Plan – Scoping Stage |chapter-url=http://www.environment-agency.gov.uk/commondata/acrobat/app_a_1243533.pdf |publisher=[[Environment Agency]] |location=UK |url-status=dead |archive-url=https://web.archive.org/web/20070710054700/http://www.environment-agency.gov.uk/commondata/acrobat/app_a_1243533.pdf |archive-date=2007-07-10 }}</ref> and in [[planetary science]].