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 sci ...

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 gl ...

) 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 primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. 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, a ...

and all the data is in the

public domain The public domain (PD) consists of all the creative work A creative work is a manifestation of creative effort including fine artwork (sculpture, paintings, drawing, sketching, performance art), dance, writing (literature), filmmaking, ...

. 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),

contour Contour may refer to: * Contour (linguistics), a phonetic sound * Pitch contour * Contour (camera system), a 3D digital camera system * Contour, the KDE Plasma 4 interface for tablet devices * Contour line, a curve along which the function ha ...

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 Ea ...

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,

BIL BIL or Bil may refer to: Mythology * Bil, a Norse goddess * Bil (Mandaeism), the Mandaean name for Jupiter People * Bil Baird (1904–1987), American puppeteer * Bil Dwyer (1907-1987), American cartoonist and humorist * Bil Dwyer (born 1962), A ...

, 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 na ...

(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