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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 ...
Digital terrain modelling. A digital terrain model (DTM) is a mathematical model that represents Earth's visible terrain surfaces. A DTM transforms discernible LiDAR data points into a continuous 3-D surface, the model connects discrete points with distinct height values to form planes. Thus, structural geologists are able to derive structural ...
DTED (or Digital Terrain Elevation Data) is a standard of digital datasets which consists of a matrix of terrain elevation values, i.e., a Digital Elevation Model. This standard was originally developed in the 1970s to support aircraft radar simulation and prediction. Terrain elevations are described as the height above the Earth Gravitational ...
Airborne lidar sensors are used by companies in the remote sensing field. They can be used to create a DTM (Digital Terrain Model) or DEM (Digital Elevation Model); this is quite a common practice for larger areas as a plane can acquire 3–4 km (2– 2 + 1 ⁄ 2 mi) wide swaths in a single flyover. Greater vertical accuracy of below 50 mm (2 ...
The Shuttle Radar Topography Mission ( SRTM) is an international research effort that obtained digital elevation models on a near-global scale from 56°S to 60°N, [2] : 4820 to generate the most complete high-resolution digital topographic database of Earth prior to the release of the ASTER GDEM in 2009. SRTM consisted of a specially modified ...
An advantage of using a TIN over a rasterized digital elevation model (DEM) in mapping and analysis is that the points of a TIN are distributed variably based on an algorithm that determines which points are most necessary to create an accurate representation of the terrain. Data input is therefore flexible and fewer points need to be stored ...
A digital terrain model (DTM) represents specifically the ground surface while DEM and DSM may represent tree top canopy or building roofs. While a DSM may be useful for landscape modeling , city modeling and visualization applications, a DTM is often required for flood or drainage modeling, land-use studies , [14] geological applications, and ...
GTOPO30. GTOPO30 is a digital elevation model for the world, developed by United States Geological Survey (USGS). It has a 30- arc second resolution (approximately 1 km), [1] and is split into 33 tiles stored in the USGS DEM file format . According to DTED and USGS DEM the absolute vertical accuracy of GTOP30 varies from ±30 meters.