GeoSpacialResources



USGS Digital Elevation Model/National Elevation Dataset

Text for USGS Digital Elevation Model/National Elevation Dataset

  • USGS Data Products
  • "The National Elevation Dataset (NED) is the primary elevation data product of the USGS. The NED is a seamless dataset with the best available raster elevation data of the conterminous United States, Alaska, Hawaii, and territorial islands. The NED is updated on a nominal two month cycle to integrate newly available, improved elevation source data. All NED data are public domain. The NED is derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. NED data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83).

    All elevation values are in meters and, over the conterminous United States, are referenced to the North American Vertical Datum of 1988 (NAVD 88). The vertical reference will vary in other areas. NED data are available nationally (except for Alaska) at resolutions of 1 arc-second (about 30 meters) and 1/3 arc-second (about 10 meters), and in limited areas at 1/9 arc-second (about 3 meters). In most of Alaska, only lower resolution source data are available. As a result, most NED data for Alaska are at 2-arc-second (about 60 meters) grid spacing, Part of Alaska is available at the 1- and 1/3-arc-second resolution, and plans are in development for a significant improvement in elevation data coverage of the state.

    The NED serves as the elevation layer of The National Map, and provides basic elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use NED data for global change research, hydrologic modeling, resource monitoring, mapping and visualization, and many other applications."

    NED data can be downloaded in "tiles" buy using the USGS National Map tool.

    USGS National Elevation Dataset (NED ) : Gesch, D.B., 2007, The National Elevation Dataset, in Maune, D., ed., Digital Elevation Model Technologies and Applications: The DEM Users Manual, 2nd Edition: Bethesda, Maryland, American Society for Photogrammetry and Remote Sensing, p. 99-118. Gesch, D., Oimoen, M., Greenlee, S., Nelson, C., Steuck, M., and Tyler, D., 2002, The National Elevation Dataset: Photogrammetric Engineering and Remote Sensing, v. 68, no. 1, p. 5-11.



    NASA SRTM - Shuttle Radar Topography Mission

    USGS maintained elevation data ( not be be confused with the NED ) that is used with the SPLAT ITM/ITWOM infrastructure.

    "The Shuttle Radar Topography Mission (SRTM) obtained elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of Earth. SRTM consisted of a specially modified radar system that flew onboard the Space Shuttle Endeavour during an 11-day mission in February of 2000.

    SRTM is an international project spearheaded by the National Geospatial-Intelligence Agency (NGA) and the National Aeronautics and Space Administration (NASA)."

  • NASA SRTM Mission and Explaination
  • NASA SRTM Data Downloads ( USA 1 arc-second )
  • NASA SRTM Data Downloads ( Global 3 arc-second )


  • GoogleMaps Elevation Web Service API

    "The Elevation API provides elevation data for all locations on the surface of the earth, including depth locations on the ocean floor (which return negative values). In those cases where Google does not possess exact elevation measurements at the precise location you request, the service will interpolate and return an averaged value using the four nearest locations."

  • The Google Elevation API


  • USGS Elevation Web Service API

    "The Elevation Query Web Service returns the elevation in feet or meters for a specific latitutde/longitude (WGS 1984) point from the USGS Seamless Elevation datasets hosted at EROS. The elevation values returned default to the best-available data source available at the specified point.

    Alternately, this service may return the value from a specified data source, or from all data sources. If unable to find data at the requested point, this service returns an extremely large, negative value (-1.79769313486231E+308). View the detailed Elevation Service Methods description for more information on the methods and parameters used in this service. Visit http://gisdata.usgs.gov/ to view other EROS Web Services."

  • The USGS Elevation REST Web Service
  • The USGS has a comprehensive suite of National Map web tools with Service Endpoints



    GeoSpacial Solutions

    A great collection of JavaScript/ECMAScript functions used to deduce all kinds of measurements between given latitude/longitude pairs, as well as library that presents all popular geospatial data formats with a common data abstraction or view in to the data.

  • MoveableType (1) - GeoSpacial Coordinate Functions
  • MoveableType (2) - GeoSpacial Coordinate Functions
  • GDAL - Geospatial Data Abstraction Library
  • Geographic Contour Calculation Guidelines - Wireless Innovation Forum's succinct interpretation of FCC rules



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