Digital elevation models

Learn about DSMs and DTMs.


Overview

A digital elevation model (DEM) is a representation of elevation data. DEMs are usually generated from remotely sensed data collected by satellites, drones, and planes.

Types of DEMs

A DEM can be a digital surface model (DSM) or a digital terrain model (DTM). Other derivative products of elevation models include slope, aspect, curvature, shaded relief, and normalized DSMs.

A DSM illustrates the Earth’s surface and all objects on it, while a DTM is a bare-earth model devoid of human-made and natural structures. A DTM can be derived from a DSM.

A profile view diagram of a green DSM line following the tops of houses and other surface structures, while a blue DTM line follows the bare Earth elevation

DSM

A representation of the surface of the Earth with man-made objects and vegetation. DSMs are used for the following use cases:

  • Urban planning
  • Vegetation management
  • Runway approach zone encroachment
  • Orthorectification

A DSM visualized using singleband pseudocolor and hillshade, representing surface features like buildings and trees

DTM

A representation of the bare Earth elevation without man-made objects and vegetation. DTMs are used for the following use cases:

  • Reducing gravity measurements
  • Analyzing terrain
  • Gravimetry
  • Physical geodesy

A DTM visualized using singleband pseudocolor and contour lines, representing bare Earth elevation

Hybrid

A digital elevation model that blends DSM and DTM characteristics by leveling small objects and urban structures to approximate bare earth, while retaining larger vegetation and terrain features with moderate smoothing. Hybrid DEMs are used for the following use cases:

  • Orthorectification
  • Terrain modeling
  • Cartographic mapping
  • Environmental monitoring

Availability

CollectionModel typeResolutionSystem type and data sourceAvailabilityCoverage
Airbus ElevationDSM
DTM
50 cm, 1 m, 4 mSatellite
(Pléiades Neo, Pléiades)
Upon requestGlobal
Bluesky ElevationDSM
DTM
25 cm, 2 m, 5 mAerial
(Bluesky Aerial)
Upon requestUK
Globhe ElevationDSM
DTM
1–10 cmDrone
(Globhe Optical and LIDAR)
Upon requestGlobal
Hexagon Elevation DSMDSM30 cm, 60 cmAerial
(Hexagon Aerial)
Off-the-shelfNorth America and Europe
NEXTMapDSM
DTM
1 m, 6 m, 10 mAerial
(SAR and LIDAR)
Off-the-shelfAreas all over the world
PlanetDEMDSM30 mSatellite
(ALOS World 3D - 30m, NASADEM)
Upon requestGlobal
Vexcel ElevateDSM
DTM
5.5–7.5 cm, 15–20 cmAerial
(Vexcel Aerial)
Off-the-shelfAreas all over the world
WorldDEM NeoDSM
DTM
5 mSatellite
(TerraSAR‑X)
Off-the-shelfGlobal*
WorldDEM4OrthoHybrid24 mSatellite
(TerraSAR‑X)
Off-the-shelfGlobal*

*The geographic coverage is global, but certain areas are restricted.

Troubleshooting

What is a vertical datum in a DEM?

DEMs are referenced to a vertical datum. Depending on the model being used, a geodetic vertical datum takes a specific zero point, to which heights of various points will be referenced. The datum is needed for accurate measures of height above a surface.

Learn more


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