What map projections are used in The National Map tiled base map services and dynamic overlay services?

The projection used for all tiled base map services in The National Map is the World Geodetic System 1984 (WGS 84) Web Mercator (Auxiliary Sphere) so that base map services can be used in combination with other common viewers. See Spatial Reference SR-ORG:6928 and Spatial Reference SR-ORG:7483.

Dynamic overlay services are in WGS84 (see Spatial Reference EPSG:4326) but can be reprojected as needed. In the past, USGS map services were in WGS 84 with units of geographic decimal degrees, but the WGS 84 Web Mercator (Auxiliary Sphere) projection was implemented to allow users the greatest level of freedom in mixing these services with other commonly used web map applications that exist today.

 

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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...

What are the projection, horizontal and vertical datum, and resolution for 3D Elevation Program (3DEP) standard DEMs?

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...

How are different map projections used?

The method used to portray a part of the spherical Earth on a flat surface, whether a paper map or a computer screen, is called a map projection. No flat map can rival a globe in truly representing the surface of the entire Earth, so every flat map misrepresents the surface of the Earth in some way. A flat map can show one or more--but never all--...

What projection are the imagery services in The National Map viewer?

Imagery services in The National Map (TNM) Viewer use WGS 1984 Web Mercator (Auxiliary Sphere) . The USGS ImageryOnly Service (under Base Maps) is cached (pre-generated) at this projection. Imagery services can be easily reprojected to many other popular projections for use in GIS desktop applications as background services.
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Date published: October 23, 2019

USGS Digital Elevation Models (DEM) Switching to New Distribution Format

In support of ongoing efforts to provide efficient, cloud ready, open data formats, the U.S. Geological Survey National Geospatial Program is announcing plans to migrate its 3D Elevation Program (3DEP) Digital Elevation Models (DEM) to a new data delivery format called Cloud Optimized Geotiff (COG) during the first half of fiscal year 2020.

Date published: July 31, 2017

Mapping Public Lands in the United States

The Protected Areas Database of the United States (PAD-US) is the official inventory of public parks and other protected areas in all U.S. states and territories.

Date published: July 5, 2017

Finding Yourself Outdoors

Updated USGS digital topographic maps feature more trails and other recreation points of interest

Date published: January 23, 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.

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Mercator the Man
July 18, 2017

Gerardus Mercator

Screen shot of US Topo Story Map
August 18, 2016

US Topo Story Map – Topographic Maps for the Nation

US Topo Story Map – Topographic Maps for the Nation

October 27, 2015

Using US Topo and Historic Topo Maps on your Mobile Device

Lesson 6a: Using USGS US Topo and Historic Topographic Maps on your Mobile Device - This video demonstrates how to download and use US Topo and Historic Topographic maps on a mobile device.

November 18, 2004

PubTalk 11/2004 — From Plane Tables to Pixels

The Revolution in Mapping at the U.S. Geological Survey

by Susan P. Benjamin, Research Geographer

  • Mapping the United States in the 19th century was arduous, dangerous work; flash floods, bears, and bandits were just a few hazards
  • By the mid-20th century, aerial photography, photogrammetry, and stereophoto pairs, allowed