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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 ...
In modern mapping, a topographic map or topographic sheet is a type of map characterized by large- scale detail and quantitative representation of relief features, usually using contour lines (connecting points of equal elevation), but historically using a variety of methods. Traditional definitions require a topographic map to show both ...
In computer graphics, a triangulated irregular network ( TIN) [1] is a representation of a continuous surface consisting entirely of triangular facets (a triangle mesh ), used mainly as Discrete Global Grid in primary elevation modeling . The vertices of these triangles are created from field recorded spot elevations through a variety of means ...
Interferometric synthetic aperture radar, abbreviated InSAR (or deprecated IfSAR), is a radar technique used in geodesy and remote sensing.This geodetic method uses two or more synthetic aperture radar (SAR) images to generate maps of surface deformation or digital elevation, using differences in the phase of the waves returning to the satellite or aircraft.
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 ...
The digital elevation model (DEM) is a raster-based digital dataset of the topography (hypsometry and/or bathymetry) of all or part of the Earth (or a telluric planet). The pixels of the dataset are each assigned an elevation value, and a header portion of the dataset defines the area of coverage, the units each pixel covers, and the units of ...
For broader coverage of this topic, see Cartographic design. USGS topographic map of Stowe, Vermont with contour lines at 20-foot intervals. Terrain cartography or relief mapping is the depiction of the shape of the surface of the Earth on a map, using one or more of several techniques that have been developed.
USGS DEM. The USGS DEM standard is a geospatial file format developed by the United States Geological Survey for storing a raster -based digital elevation model. It is an open standard, and is used throughout the world. It has been superseded by the USGS's own SDTS format but the format remains popular due to large numbers of legacy files, self ...