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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.
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. [2]
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.
The National Elevation Dataset (NED) consists of high precision topography or ground surface elevation data (digital elevation model) for the United States. It was maintained by the USGS and all the data is in the public domain. Since the 3D Elevation Program came online, the NED was subsumed [1] into The National Map as one of its layers of ...
1-arc second global digital elevation model (30 meters) is available from the United States Geological Survey web site. [17] The United States Government announced on September 23, 2014 over a United Nations Climate Summit that the highest possible resolution of global topographic data derived from the SRTM mission will be released to public. [18]
In the 1980s and 1990s, digital elevation models were often obtained by scanning and digitizing the contours on paper topographic maps, which were then converted to a TIN or a gridded DEM. [13] More recently, the DEM is obtained by aerial or satellite remote sensing, using stereophotogrammetry, lidar, or radar. [14]
Pages in category "Digital elevation models" ... USGS DEM This page was last edited on 18 August 2022, at 05:48 (UTC). Text is available under the Creative Commons ...
Georeferenced map images are available from the USGS as digital raster graphics (DRGs) in addition to digital data sets based on USGS maps, notably digital line graphs (DLGs) and digital elevation models (DEMs). In 2015, the USGS unveiled the topoView website, a new way to view their entire digitized collection of over 178,000 maps from 1884 to ...