(DEM) A raster file containing elevations at regularly-spaced surface coordinates over an area. Specialized computer software can interpret this data and create a three-domentional rendering of the surface, or analyze the terrain in various ways. See Also: raster More information on DEMs.
A data file of a topographic surface arranged as a set of x,y,z coordinates where z represents surface elevation. It is the digital equivalent of the elevation data portrayed on a topographic base map.
A representation of the topography of the Earth in digital format, that is, by coordinates and numerical descriptions of altitude.
a computer map of elevation across a land surface
a digital representation of the Earth's surface
an ASCII or binary file that contains only spatial elevation data in a regular gridded pattern in raster format
an ordered array of ground elevations relative to a datum
a representation of the earth's surface for a geographic area stored in a digital file containing regularly spaced point locations with an elevation attribute
a very simple database that specifies a coordinate, and its corresponding elevation
A digital cartographic/geographic dataset of elevations (topography) in xyz coordinates. The terrain elevations for ground positions are sampled at regularly-spaced horizontal intervals. DEMs are derived from contour lines and/or photogrammetric methods using USGS 7.5-minute, 15-minute, 2-arc-second (30- by 60-minute), and 1-degree (1:250,000-scale) topographic quadrangle maps. Digital elevation models are typically used to represent terrain relief.
file with terrain elevations recorded at the intersections of a fine grid and organized by quadrangle to be the digital equivalent of the elevation data on a topographic base map.
A digital representation of a topographic surface. Elevation values may be stored in a regular grid of values, one for each cell, a regular lattice of points or in a 'triangulated irregular network' (TIN) of points.
Digital representation of the elevation of locations on the land surface. DEM is used in reference to a set of elevation values representing elevations at points in a grid on the Earth's surface.
A regular pattern of ground elevation observations maintained in digital form. These can be used to generate contour lines and Triangulated Irregular Networks (TINs) which look like wire frame representations of the terrain. They are also used in the process of orthogonalizing air photos.
A map representing the elevation of the land surface.
A digital image of geographical features consisting of a grid, in which the colour of each cell reflects an average elevation above or below sea level. ( modèle altimétrique numérique (MAN))
A 3-D model of the Earth's surface represented by masspoints and breaklines. Less rigorous (not as densely collected) than a DTM. A DEM does not support contour modeling and is primarily used for orthorectification of aerial photography to the Earth's surface.
Gridded representation of elevation.
A raster storage method developed by the US Geological Survey (USGS) for elevation data.6 The format of the USGS Elevation data sets.
A set of points which defines the terrain as numbers for computer applications. This data may be used to draw contours, make ortho photos, slope maps, and drive fire models.
A digital representation of a continuous variable over a two- dimensional surface by a regular array of z values referenced to a common datum. Digital elevation models are typically used to represent terrain relief. Also referred to as 'digital terrain model' (DTM).
Terrain elevation data organized by quadrangle and provided in digital form.
A computer representation of the terrain surface consisting of spot elevation data. DEM data can be used for orthophoto rectification, but is not adequate for contour determination.
Computer file with elevations recorded for the intersections of a fine- grained latitude/longitude grid; the digital equivalent of a topographic base map; abbreviated DEM.
a digital elevation model is a digital file consisting of terrain elevations for ground positions at regularly-spaced horizontal intervals.
A digital elevation model (DEM) is a type of Digital terrain model, recording a topographical (geomorphometric) representation of the terrain of the Earth or another surface in digital format. DEM's record altitude in a raster format. That is, the map will normally divide the area into rectangular pixels and store the elevation of each pixel.