The National Elevation Dataset is a new elevation product assembled by the U.S. Geological Survey (USGS). It was designed to provide national elevation data in a seamless form with a consistent datum, elevation unit, and projection. Data corrections were made in the assembly process to minimize artifacts, permit edge matching, and fill sliver areas of missing data.  

Specifications

• Coverage: Entire United States
• Source Data:  USGS DEM data (enhanced)
• Projection: Geographic, NAD 83,GRS 80, decimal degrees
• Resolution: one arc-second (approximately 30 meters) for the conterminous United States, Hawaii, and Puerto Rico and a resolution of two arc-seconds for Alaska.
• Each file is delivered in a 1x1 degree block.  DDS can provide each file as individual quads- Call for special requests.
• Media: CD, FTP, Hard-drive

Available Formats

• USGS Standard DEM file format
• ESRI GRID
• .BIL (Intel or Motorola byte order)
• Client specified format (custom pricing).  Call for special requests.

USGS NED Fact Sheet (125 Kb)

Digital elevation model (DEM) data are arrays of regularly spaced elevation values referenced horizontally either to a Universal Transverse Mercator (UTM) projection or to a geographic coordinate system. The grid cells are spaced at regular intervals along south to north profiles that are ordered from west to east. The U.S. Geological Survey (USGS) produces five primary types of elevation data: 7.5-minute DEM, 30-minute DEM, 1-degree DEM, 7.5-minute Alaska DEM, and 15-minute Alaska DEM.

Specifications

USGS DEM Fact Sheet (81 Kb)

Available Projections

• UTM - NAD27 / NAD83 / WGS72 / WGS84
• State Plane NAD27 / NAD83
• Latitude / Longitude - NAD27 / NAD83 / WGS72 / WGS84

Available Formats

• USGS Standard DEM file format
• ESRI GRID
• ASCII Text, X,Y,Z format