U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2009–3053

Reprinted April 2010

The National Map—Elevation

Printed on recycled paper

National Elevation Dataset

The National Elevation Dataset (NED) is the primary 

elevation data product produced and distributed by the USGS. 

The NED provides seamless raster elevation data of the conterminous United States, Alaska, Hawaii, and the island territories. 

The NED is derived from diverse source data sets that are processed to a specification with a consistent resolution, coordinate 

system, elevation units, and horizontal and vertical datums. The 

NED is the logical result of the maturation of the long-standing 

USGS elevation program, which for many years concentrated 

on production of topographic map quadrangle-based digital 

elevation models. 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.

The NED is a multi-resolution dataset that is updated 

bimonthly to integrate newly available, improved elevation 

source data. NED data are available nationally at grid spacings 

of 1 arc-second (approximately 30 meters) for the conterminous 

United States, and at 1/3 and 1/9 arc-seconds (approximately 

10 and 3 meters, respectively) for parts of the 

United States. Most of the 

NED for Alaska is available at 2-arc-second (about 

60 meters) grid spacing, 

where only lower resolution source data exist. Part 

of Alaska is available at the 

1/3-arc-second resolution, 

and plans are in development for a significant 

upgrade in elevation data 

coverage of the State over 

the next 5 years. Specifications for the NED include 

the following:

• Coordinate system: 

Geographic (decimal 

degrees of 

latitude and longitude),

• Horizontal datum: North 

American Datum of 

1983 (NAD 83),

• Vertical datum: North 

American Vertical 

Datum of 1988 (NAVD 88) over the conterminous United 

States and varies in other areas, and

• Elevation units: Decimal meters.

Spatially Referenced Metadata

NED data are documented in compliance with the Federal 

Geographic Data Committee’s Content Standard for Digital 

Geospatial Metadata. The footprint of each source dataset is 

retained during NED assembly to provide a spatial context. The 

native attributes of each source dataset, such as the original 

resolution and production method, as well as a description of 

the assembly process, are linked to these footprints. The set of 

footprints provides spatially referenced metadata as an attributed geospatial data layer. Through the metadata, information 

regarding the source data is available for any area of the NED. 

For example, a user can access the spatially referenced metadata to evaluate the source data over a project area to determine 

applicability of the NED for a specific use.

A shaded-relief representation of the National Elevation Dataset (NED) covering the United States. Elevation 

is portrayed as a range of colors, from dark green for low elevations to white for high elevations.
Applications of Elevation Data

Elevation data are an essential part of many earth science 

applications. The NED is used for such diverse purposes as:

• Providing shaded-relief backgrounds,

• Generating contours, synthetic drainage networks, or watershed delineations,

• Classifying land cover,

• Geometrically correcting remotely sensed data (orthophoto 

rectification),

• Deriving landform characteristics such as slope and aspect, 

• Modeling applications such as hydraulic and hydrologic 

studies,

• Dispersion modeling,

• Predicting wildland fire behavior,

• Flash flood forecasting,

• Regional soil erosion,

• Climate data analysis,

• Vegetation height estimation,

• Air traffic safety, and

• Flight simulation and video games.

Data Availability and Plans

Elevation data are available from the NED in a seamless, 

nationally consistent form through the USGS The National 

Map Seamless Server, http://seamless.usgs.gov/ The National 

Map Seamless Server allows users to download, at no cost, an 

area of interest by drawing a box, defining coordinates, or using 

available templates to extract areas. These elevation data also 

are available through a bulk data delivery system, (email bulkdatainfo@usgs.gov for information), and in the future will be 

available through the Tiled Data Distribution System accessible 

through The National Map Seamless Server.

The NED offers multiple layers, at 1, 1/3 and 1/9 arcsecond (approximately 30, ~10 and 3.3 meters, respectively). 

Where available, higher resolution data will replace the current 

NED content, providing a continually upgraded national multiresolution dataset. Higher resolution layers will be populated 

through the integration of data from various sources, using new 

technologies, and will be acquired through partnerships with 

Federal, State, and local partners, providing access to the best 

available local information. Lidar derived elevation data are 

the primary means currently (2009) being used to upgrade the 

NED. A complementary USGS activity to the NED is the Center 

Shaded relief images of an area in North Carolina derived from the three resolutions available in the NED.

Example of a 30-meter grid spacing

Example of a 10-meter grid spacing

Example of a 3-meter grid spacing

National 

Elevation 

Dataset
The Nation Needs The National Map

As one of the cornerstones of the U.S. 

Geological Survey’s (USGS) National 

Geospatial Program, The National Map is 

a collaborative effort among the USGS and 

other Federal, State, local, and Tribal partners 

to improve and deliver topographic information for the Nation. The National Map has 

many uses ranging from recreation to scientific 

analysis to emergency response. The National 

Map is easily accessible for display on the 

Web, as products and services, and as downloadable data. The geographic information 

available from The National Map includes 

orthoimagery (aerial photographs), elevation, 

geographic names, hydrography, boundaries, transportation, structures, and land cover. 

Other types of geographic information can be 

added within the viewer or brought in with 

The National Map data into a Geographic 

Information System to create specific types of 

maps or map views. 

The National Map is a significant 

contribution to the National Spatial Data 

Infrastructure (NSDI) and provides high quality, integrated geospatial data and improved 

products and services including new generation digital topographic maps. The National 

Map also is foundational to implementation of 

the Department of the Interior (DOI) Geospatial Modernization Blueprint and meeting the 

DOI mission. The National Map underpins 

the USGS Science Strategy, which is based 

on a systems approach to help address multifaceted issues, provide better understanding of 

earth processes, and evaluate broad causes and 

consequences of the use and management of 

natural resources. The National Map promotes 

interdisciplinary science by providing nationally consistent, trusted geospatial data, and 

establishing a consistent national geographic 

context.

Surface hydrology features in southern California derived from 

lidar elevation data.

Lidar-derived bare earth elevation data aids storm response and 

recovery operations.

for lidar Information Coordination and Knowledge (CLICK) 

(http://lidar.cr.usgs.gov/). Data acquired for distribution through 

the CLICK also are used as a source of high-resolution bare 

earth elevation data to upgrade the NED. In addition, through 

the CLICK, users have access to the full-return point cloud 

form of lidar data that is included in the NED as bare earth gridded elevation data.

Partnership Opportunities

Organizations interested in partnering with the USGS to 

develop elevation data for The National Map should contact 

the USGS mapping liaison in their State. The list of liaisons is 

available at http://www.usgs.gov/ngpo/ngp_liaisons.html 
Further Information

Further information about The National Map can be viewed or downloaded at http://nationalmap.gov/. Further information on the NED, including details on NED history, production, accuracy assessment, and applications, is available on the 

NED Web site (http://ned.usgs.gov/) and in the following publications:

Gesch, D.B., 2007, Chapter 4 – The national elevation dataset, in Maune, D., ed., Digital elevationl model technologies and 

applications: The DEM Users Manual, (2nd ed.): 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.

For information on other USGS product and services, call 1-888-ASK-USGS or visit the general interest publications 

Web site on maps, imagery, and related publications at http://www.usgs.gov/pubprod/. For additional information, visit the 

http://ask.usgs.gov/ Web site or the USGS home page at http://www.usgs.gov/.

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Ground surface elevation and other natural and man-made features are depicted in this lidar dataset of Sioux Falls, South Dakota.