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The USGS Gap Analysis Program maintains four primary data sets: land cover, protected areas, species and aquatic. The GAP Land Cover Data Set is the most complete map ever produced of vegetative associations for the US. Classified into 551 ecological systems, and 32 modified ecological systems (where human impacts have had an effect).
USGS DEM – The USGS' Digital Elevation Model GTOPO30 – Large complete Earth elevation model at 30 arc seconds, delivered in the USGS DEM format; DTED – National Geospatial-Intelligence Agency (NGA)'s Digital Terrain Elevation Data, the military standard for elevation data; World file – Georeferencing a raster image file (e.g. JPEG, BMP)
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.
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 software stores 2-D grids as COARDS-compliant netCDF files and comes with a comprehensive collection of free GIS data, such as coast lines, rivers, political borders and coordinates of other geographic objects. Users convert further data (like satellite imagery and digital elevation models) from other sources and
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 ...
Currently, the best source for nationwide LiDAR availability from public sources is the United States Interagency Elevation Inventory (USIEI). [1] The USIEI is a collaborative effort of NOAA and the U.S. Geological Survey, with contributions from the Federal Emergency Management Agency, the Natural Resources Conservation Service, the US Army Corps of Engineers, and the National Park Service.
A national lidar dataset refers to a high-resolution lidar dataset comprising most—and ideally all—of a nation's terrain. Datasets of this type typically meet specified quality standards and are publicly available for free (or at nominal cost) in one or more uniform formats from government or academic sources.