Are 3D Elevation Program (3DEP) contour lines updated and what sources were used to create them?

When significant changes in the landscape have occurred, contours will be updated on an as-needed basis.  

The 100-foot contours were derived from 3DEP (formerly National Elevation Dataset) one arc-second resolution data that was sub-sampled to a cell size of three arc-second. The 50-foot contours were also derived from one arc-second data. Large-scale contours were derived from 1/3 arc-second resolution data for US Topo products.   

The seamless digital elevation models (DEMs) used to create the contour lines are enhanced as we collect lidar over the US through the 3DEP program. 

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What types of elevation datasets are available, what formats do they come in, and where can I download them?

Digital elevation data for the United States and its territories are available through The National Map Downloader . Click the “Help” link at the top of the page for detailed instructions on how to find and download data. There is a separate site for The National Map Services . The 3D Elevation Program (3DEP) products and services available...

How do I find, download, or order topographic maps?

The U.S. Geological Survey (USGS) has been the primary civilian mapping agency of the United States since 1879. The best known USGS maps are the 1:24,000-scale topographic maps, also known as 7.5-minute quadrangles. Download all dates and scales of USGS topographic maps free of charge from the following applications or order paper copies of all...

Are depression contours identified in 3D Elevation Program (3DEP) contour products?

Yes, depression contours are identified with tick marks, but only in large scale contours from 36K to 18K.

What geographic areas do 3D Elevation Program (3DEP) contours cover?

Contours cover the conterminous United States at small (578K/289K), medium (144K/72K), and large (36K/18K) scales.

What are the projection, horizontal and vertical datum, format, and distributed tile extent of 3D Elevation Program (3DEP) contours?

Contours are not projected, but are provided in geographic coordinates (latitude and longitude) in units of decimal degrees, and horizontally referenced to the North American Datum of 1983. Contour elevation values are vertically referenced to the North American Vertical Datum of 1988. Contours are staged in Esri File Geodatabase 10.1 or Shapefile...

How do I report errors in 3D Elevation Program (3DEP) elevation data?

If you think you’ve found an error in USGS elevation data, please send an email to tnm_help@usgs.gov . We will add the reported information to our "Digital Elevation Model Issues" data log for further analysis and possible correction. Spikes, pits, seam-line anomalies, and other data errors are of concern to us. We are working to correct or...

How accurate are elevations generated by the Elevation Point Query Service in The National Map?

The National Map’s   Elevation Point Query Service returns elevations that are interpolated from the 1/3 arc-second  3D Elevation Program  (3DEP) DEM dataset. These interpolated point elevations are not official and do not represent precisely measured ground surveyed values.     Elevations derived for a specific location using the Elevation Point...

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

They both might be correct. The reason that the elevations do not agree might be because they are set on different datums. Most maps use NAD27 and the elevations are based on mean sea level. Your GPS receiver uses WGS84 and the elevations are based on the NAD83 ellipsoid. These datum shifts can result in difference of tens of meters horizontal and...
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Date published: August 8, 2018

New Elevation Map Service Available From the USGS 3D Elevation Program

The USGS 3D Elevation Program (3DEP) announces the availability of a new dynamic map service.

Date published: May 23, 2018

Keeping Current with Map Services Made Easier

The National Map provides a new Simple Notification Service and has new URLs for some of its thematic cartographic map services.

Date published: January 24, 2017

Maps Made with Light Show the Way

The topic, officially, was water. But during a scientific conference in Butte, Montana, in 2013, earthquake expert Michael Stickney glimpsed something unexpected in a three-dimensional lidar image of the Bitterroot Valley in nearby Missoula.

Date published: August 18, 2016

Story Map - Topographic Maps for the Nation

The USGS National Geospatial Program has released an interactive Story Map giving viewers an overview of the US Topo map program

Date published: February 22, 2016

EarthWord – Prominence

Prominence is a term in topography that refers to the elevation of a summit relative to its surrounding terrain. This is different from its overall elevation, which measures the height of the summit above sea level.

Filter Total Items: 4
May 11, 2018

New 3D Model of the Drained Crater at Pu‘u ‘Ō‘ō

During an overflight on May 11, we collected thermal images of the crater at Pu‘u ‘Ō‘ō and created an updated 3D model of the crater geometry. The collapse on April 30 produced a large cavity, with the deepest point roughly 350 m (1150 feet) below the crater rim.

A comparison of an air photo and a lidar image of an area along Secondary Road and Camp Creek
April 14, 2016

Comparison Lidar and Air Photo

A comparison of an air photo and a lidar image of an area along Secondary Road and Camp Creek, 12 miles north of John Day, OR. The lidar image allows identification of landslide activity that is otherwise masked by trees. (Photo courtesy of the Oregon Department of Geology and Mineral Industries).

video thumbnail: Using bare-earth LiDAR imagery to reveal the Tahoe - Sierra frontal fault zone Lake Tahoe, California.
September 29, 2008

Using bare-earth LiDAR imagery to reveal the Tahoe - Sierra frontal fault zone Lake Tahoe, California.

This video provides a visual example of how airborne LiDAR (Light D
etection And Ranging) imagery penetrates dense forest cover to reveal
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

Attribution: Natural Hazards
AK Mount McKinley A-3 US Topo (Browse Image for Story Map)
December 31, 1954

AK Mount McKinley A-3 US Topo (Browse Image for Story Map)

AK Mount McKinley A-3 US Topo (Browse Image for Story Map)