The National Map
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Elevation
The National Elevation Dataset (NED) is a seamless raster product primarily derived from USGS 10- and 30-meter Digital Elevation Models (DEMs), and, increasingly, from higher resolution data sources such as light detection and ranging (lidar), interferometric synthetic aperture radar (ifsar), and high-resolution imagery. NED data are available from The National Map Viewer as 1 arc-second (approximately 30 meters) for the CONUS, and at 1/3 and 1/9 arc-seconds (approximately 10 and 3 meters, respectively) for parts of the United States. NED resolution for Alaska is primarily 2 arc-seconds (approximately 60 meters) but is rapidly being replaced with 5-meter resolution ifsar data State-wide and lidar over select areas. Lidar point cloud data is available for download from Earth Explorer. In response to growing needs for high-quality topographic data and for a wide range of other three-dimensional representations of the Nation's natural and constructed features, the National Geospatial Program has introduced the 3D Elevation Program (3DEP) initiative, the goal of which is to systematically collect enhanced elevation data in the form of high-quality lidar data over the conterminous United States (CONUS), Hawaii, and the U.S. territories. Ifsar data will be collected over Alaska, where cloud cover and remote locations preclude the use of lidar over much of the State. The 3DEP initiative will result in higher resolution and more accurate data as well as new products in the future.
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