Digital elevation model
3D computer graphics representation of elevation data for terrain.
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, moon, or asteroid. A "global DEM" refers to a discrete global grid. DEMs are used often in geographic information systems (GIS), and are the most common basis for digitally produced relief maps. A digital terrain model (DTM) represents specifically the ground surface while DEM and DSM may represent tree top canopy or building roofs.
- field
- Geographic information systems, remote sensing, planetary science
- known_for
- 3D representation of elevation data for terrain and overlaying objects
- types
- Raster (grid) and vector-based triangular irregular network (TIN)
- acquisition_methods
- Photogrammetry, lidar, IfSAR, InSAR, land surveying
- common_uses
- Relief maps, flood modeling, 3D visualizations, satellite navigation
Lore & Background
There is no universal usage of the terms digital elevation model (DEM), digital terrain model (DTM) and digital surface model (DSM) in scientific literature. In most cases the term digital surface model represents the earth's surface and includes all objects on it, while the digital terrain model represents the bare ground surface without any objects like plants and buildings. DEM is often used as a generic term for DSMs and DTMs, only representing height information without any further definition about the surface. Some datasets such as SRTM or the ASTER GDEM are originally DSMs, although in forested areas, SRTM reaches into the tree canopy giving readings somewhere between a DSM and a DTM.
Reader's Guide
Digital elevation models are foundational tools in geographic information systems and planetary science, enabling the creation of relief maps, flood and drainage modeling, and 3D visualizations. They are produced through remote sensing techniques such as interferometric synthetic aperture radar, lidar, and stereo photogrammetry, as well as from land surveying. The quality of a DEM depends on terrain roughness, sampling density, grid resolution, interpolation algorithm, and vertical resolution. In planetary science, orbital altimetry—both laser and radar—has been used to create digital elevation maps of Mars, the Moon, Mercury, and other bodies. The term DEM is used generically for DSMs and DTMs, though distinctions exist: DTMs represent bare ground, while DSMs include surface objects like buildings and vegetation.
Did You Know?
- A DEM can be represented as a raster (grid of squares) or as a vector-based triangular irregular network (TIN).
- Planetary digital elevation maps have been made using laser altimetry for Mars (MOLA), the Moon (LOLA, LALT), and Mercury (MLA).
Frequently Asked Questions
Who is Digital elevation model?
Digital elevation model is a 3D computer-generated depiction of surface elevation for a planet, moon, or asteroid, sitting at the crossroads of GIS, remote sensing, and planetary science. It is the foundational layer that turns raw height data into a navigable terrain representation.
What are Digital elevation model's powers/role?
Its core function is supplying the elevation backbone for relief maps, flood-risk modeling, 3D terrain visualizations, and satellite navigation. It can be structured as a raster grid or a vector-based triangular irregular network depending on the precision a project demands.
How does Digital elevation model's story end?
Rather than a narrative arc, its finale is the delivered product—a finished relief map, a flood simulation, or a 3D visualization handed off to GIS software or a navigation system. Once that data is rendered and consumed by downstream tools, its run is complete.
Why is Digital elevation model important?
It is the most widely used basis for digitally produced relief maps and underpins everything from urban flood planning to satellite-based navigation. Without a standardized elevation framework like this, large-scale geographic analysis and 3D terrain rendering would lack a common reference.
How does Digital elevation model acquire its data?
Elevation values are captured through photogrammetry, lidar, interferometric synthetic aperture radar, or traditional land surveying. A key distinction fans often ask about: a DTM records only bare ground, while a DEM or DSM can include tree canopies and building rooftops on top of the terrain.
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