The National Elevation Dataset (NED) consists of high precision

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sc ...

or ground surface elevation data (

digital elevation model A digital elevation model (DEM) or digital surface model (DSM) is a 3D computer graphics representation of elevation data to represent terrain or overlaying objects, commonly of a planet, moon, or asteroid. A "global DEM" refers to a discrete g ...

) for the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

. It was maintained by the

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

and all the data is in the

public domain The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because those rights have expired ...

. Since the 3D Elevation Program came online, the NED was subsumedThe National Map elevation informati

/ref> into

The National Map ''The National Map'' is a collaborative effort of the United States Geological Survey (USGS) and other federal, state, and local agencies to improve and deliver topographic information for the United States. The purpose of the effort is to prov ...

as one of its layers of information.

Sources

The NED dataset is a compilation of data from a variety of existing high-precision datasets such as

LiDAR Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...

data (see also

National LIDAR Dataset - USA Currently, the best source for nationwide LiDAR availability from public sources is the United States Interagency Elevation Inventory (USIEI). The USIEI is a collaborative effort of NOAA and the U.S. Geological Survey, with contributions from the Fe ...

), contour maps,

USGS DEM The USGS DEM standard is a geospatial file format developed by the United States Geological Survey for storing a raster-based digital elevation model. It is an open standard, and is used throughout the world. It has been superseded by the USGS's o ...

collection,

SRTM The Shuttle Radar Topography Mission (SRTM) is an international research effort that obtained digital elevation models on a near-global scale from 56°S to 60°N, to generate the most complete high-resolution digital topographic database of E ...

and other sources which were reorganized and combined into a seamless dataset, designed to cover all the United States territory in its continuity.

Formats

Data is available in a few popular formats such as

ESRI Esri (; Environmental Systems Research Institute) is an American multinational geographic information system (GIS) software company. It is best known for its ArcGIS products. With a 43% market share, Esri is the world's leading supplier of GIS ...

ArcGRID,

GeoTIFF GeoTIFF is a public domain metadata standard which allows georeferencing information to be embedded within a TIFF file. The potential additional information includes map projection, coordinate systems, ellipsoids, datums, and everything else necessa ...

, BIL, GridFloat, and a few others.

Precision

Depending on area location, the datasets are provided with 1/9 (about 3 meters), 1/3 (about 10 m) and 1-

arcsecond A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The n ...

(about 30 m) precision.

References

External links

Elevation data in The National Map

Shaded Relief Maps of the United States
Cartography Digital elevation models {{geomorph-stub