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, archaeology
Lore & Background
The term digital elevation model (DEM) is often used as a generic term for DSMs and DTMs, though there is no universal usage in scientific literature. Some sources equalize DEM and DTM, others equalize DEM and DSM, and some define DEM as a subset of DTM. Most data providers (USGS, ERSDAC, CGIAR, Spot Image) use DEM as a generic term. Datasets such as SRTM or ASTER GDEM are originally DSMs, though in forested areas SRTM reaches into the tree canopy, giving readings between a DSM and a DTM. DTMs are created from high-resolution DSM datasets using complex algorithms to filter out buildings and other objects, a process known as 'bare-earth extraction'.
Reader's Guide
Digital elevation models are foundational tools in geographic information systems and planetary science. They enable extraction of terrain parameters for geomorphology, modeling water flow for hydrology, creation of relief maps, and rendering of 3D visualizations. DEMs are also used in engineering design, satellite navigation, line-of-sight analysis, flight simulation, precision farming, and archaeology. The quality of a DEM depends on terrain roughness, sampling density, grid resolution, interpolation algorithm, and vertical resolution. Planetary mapping uses orbital altimetry—laser or radar—to create digital elevation maps of Mars, the Moon, Mercury, and other bodies.
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?
A digital elevation model is a three-dimensional computer-generated depiction of surface heights for a planet, moon, or asteroid. It functions as the core spatial data layer in geographic information systems and remote-sensing workflows.
What are Digital elevation model's powers/role?
It encodes terrain elevations and, depending on the variant (DEM vs. DSM), also captures overlaying features such as treetops and rooftops. That structured data drives relief maps, flood simulations, 3D visualizations, satellite navigation, and archaeological site analysis.
How does Digital elevation model's story end?
Because it is a living technology rather than a finite narrative, its 'ending' is an ongoing push toward finer global grids. Newer acquisition methods like lidar, photogrammetry, and interferometric SAR keep raising resolution and coverage year after year.
Why is Digital elevation model important?
It is the single most common foundation for digitally produced relief maps and the backbone of virtually every 3D terrain visualization in GIS, planetary science, and civil engineering. Without it, modern flood modeling, satellite navigation, and archaeological surveying would lack their essential spatial reference.
What are Digital elevation model's origins and how is it acquired?
Elevation measurements are gathered through photogrammetry, lidar scanning, IfSAR/InSAR, and traditional land surveying. Those raw numbers are then organized into either a raster grid or a vector-based triangular irregular network (TIN).
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