The Shuttle Radar Topography Mission (SRTM) digital elevation dataset was collected by a modified radar system that flew on board the Space Shuttle Endeavor in February 2000, using a technique known as Interferometric Synthetic Aperture Radar (IfSAR) to...
The NED serves as the elevation layer of The National Map, and provides elevation information for earth science studies and mapping applications in the United States.
The NED is updated continually as new data become available.
To cite the NED in a publication, please use the following literature references: 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,...
Yes, lidar data are highly dense point data representing an x, y, z location, along with other attributes, of any terrestrial target reflecting the laser pulse. In addition to bare-earth, it typically will include buildings, trees, towers, and powerlines...
NED Release Notes were previously produced to provide details about the current and previous releases of the NED, its source data, and noteworthy characteristics of the dataset including accuracy, data distribution statistics, and processing notes. These...
The NED data are not projected, but are provided in geographic coordinates (latitude and longitude) in units of decimal degrees, horizontally referenced on the North American Datum of 1983. All elevation values are in units of meters typically referenced...
NED source data are selected from an inventory of standard production USGS digital elevation models (DEMs), and from an increasing number of datasets that are project- or agency-specific. Quality and currency are primary factors in determining if a...
NED data (either 2-, 1-, or 1/3-arc-second resolutions) are available in ArcGrid, GridFloat, and IMG formats. NED 1/9 arc-second data are available in IMG format only. Accompanying metadata are available in TXT, XML, and HTML with each download.
Creating shaded relief directly from NED data can be problematic, because the horizontal units are in decimal degrees but vertical units are in meters. When horizontal and vertical units aren't the same, most hill-shading functions require extra care in...