Search results
Results from the WOW.Com Content Network
The NED dataset is a compilation of data from a variety of existing high-precision datasets such as LiDAR data (see also National LIDAR Dataset - USA), contour maps, USGS DEM collection, SRTM and other sources which were reorganized and combined into a seamless dataset, designed to cover all the United States territory in its continuity.
The purpose of the effort is to provide "...a seamless, continuously maintained set of public domain geographic base information that will serve as a foundation for integrating, sharing, and using other data easily and consistently". [2] The National Map is part of the USGS National Geospatial Program. [3]
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.
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 ...
The USGS DEM format is a self-contained (single file) set of ASCII-encoded (text) 1024-byte (1024 ASCII chars) blocks that fall into three record categories called A, B, and C. There is no cross-platform ambiguity since line ending control codes are not used, and all data including numbers is represented in readable text form.
Information included in the Atlas includes accurate, seamless maps, documentation, and geospatial data that crosses political borders. This data is displayed as series of interactive map layers in an easy to use map viewer format. Most layers in the North American Environmental Atlas are at a scale of 1:1:10,000,000 or finer. [citation needed]
The Center for Earth Resources Observation and Science (EROS) is a United States Geological Survey data management, systems development, and research field center It serves as the national archive of remotely sensed images of the Earth's land surface acquired by civilian satellites and aircraft.
SRTM data, being derived from radar, represents the elevation of the first-reflected surface—quite often tree tops. So, the data are not necessarily representative of the ground surface, but the top of whatever is first encountered by the radar. Submarine elevation (known as bathymetry) data is generated using ship-mounted depth soundings.