What sources of data are used to produce the standard 3D Elevation Program (3DEP) DEMs?

3DEP standard DEMs are produced from the highest quality elevation sources within the data holdings of the USGS National Geospatial Program. As of 2015, about 25% of the conterminous U.S. coverage is from high resolution lidar and photogrammetric source, while the remainder of the conterminous U.S. and Hawaii coverage is from USGS topographic map contours. About one-third of Alaska coverage is from IFSAR 5-meter source and the balance is produced from topographic map contours. General categories of standard DEM source data are characterized below:

o  High resolution source DEMs (3 meters or better) are typically derived from lidar or digital photogrammetry, and usually with edited water bodies.

o  Moderate resolution source DEMs (4 to 10 meters) are typically derived from photogrammetrically produced contours or mass points and breaklines, or from ifsar. Although moderate resolution DEMs are presently the predominant source in 3DEP elevation data, they continue to be replaced as higher quality lidar and ifsar source data are acquired.

o  Low resolution DEM source:

  •  30 meter DEMs from 1:24,000-scale cartographic contours are only used as source in Puerto Rico and as void fill in very limited areas of the conterminous U.S.
  •  2 arc-second DEMs are a standard 3DEP product over the State of Alaska. They are derived from either cartographic contours compiled at a scale of 1:63,360, or from 1 arc-second Shuttle Radar Topography Mission (SRTM) data over the Aleutian Islands.
  •  Bathymetric DEMs for some coastal areas are collected using lidar, sonar, and other methods of subsurface terrain measurement, transformed to a common datum, and resampled to 1/9 arc-second resolution.

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What is the vertical accuracy of the 3D Elevation Program (3DEP) DEMs?

The most recently published figure of absolute vertical accuracy of the 3DEP DEMs within the conterminous United States, in terms of the National Standard for Spatial Data Accuracy (NSSDA) at 95% confidence level, is 3.04 meters. It is important to note that the vertical accuracy actually varies significantly across the U.S. because of differences...

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All 3DEP seamless DEMs are provided in geographic coordinates (longitude and latitude) in units of decimal degrees, horizontally referenced on the North American Datum of 1983 (NAD83). All elevation values are in units of meters, typically referenced to the North American Vertical Datum of 1988 (NAVD88), although the National Geodetic Vertical...

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USGS Digital elevation models (DEMs) 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 USGS acquires bare-earth...

Why don't the elevations on your maps agree with those provided by my GPS system? Which ones are correct?

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Date published: February 7, 2019

USGS 3DEP Lidar Point Cloud Now Available as Amazon Public Dataset

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video thumbnail: Elevation
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video thumbnail: Using bare-earth LiDAR imagery to reveal the Tahoe - Sierra frontal fault zone Lake Tahoe, California.
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This video provides a visual example of how airborne LiDAR (Light D
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an active fault line not detectable with conventional aerial
photography. The video shows an aerial perspective of the range front
Mt. Tallac fault, which is one of five active faults that traverse

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