Frequently Asked Questions

Mapping, Remote Sensing, and Geospatial Data

The USGS provides the mapping and digital geospatial foundation for the Nation.

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Monterey Peninsula onshore and offshore shaded-relief map
Small-scale shaded relief layers (30 arc-seconds and larger cell sizes) are derived from the USGS GTOPO30 dataset. Medium- and large-scale shaded relief layers (up to 16 arc-second cell size) are derived from the 1/3 arc-second DEM layer of The National Map.
Shaded relief map of Prince William Sound and surrounding region.
There is the shaded relief service USGSShadedReliefOnly (MapServer), which is a tile cache base map service from world scale to 18K. 
usgs_national_center_building
Since the USGS obtains most boundaries, structures, and transportation data from external sources, the frequency of updates depends on the release schedule of the source products. Boundaries updates are variable. Data content for the Structures map service is targeted for quarterly refresh cycles, while updated products are immediately available...
Image of Menol Park building
National Map data products can be downloaded through The National Map Download Client. To download data from The National Map Download Client: 1) Select the data you wish to download on the left side of the page.2) Select the resolution and format you are interested in. 3) There are several ways to define your area of interest:     Option 1: To...
Image: New Accessions Arriving at Field Records
The USGS Field Records Collection is an archive of unpublished field notes, maps, correspondence, manuscripts, analysis reports, and other data created or collected by USGS Geology Discipline scientists during field studies and other project work. The collection is located in the USGS Library in Denver, Colorado, and is available for on-premises ...
Image: Aerial View of Roadbed Collapse
Map service metadata is available in The National Map Viewer by clicking on the pull-down arrow in front of each base data layer in the table of contents under ‘Overlays’. Service metadata can also be viewed through the data layer endpoints. In addition, product-level metadata is included with data downloaded in The National Map Download Client...
Image: Railroad Tracks
Boundaries: Some of the primary sources for these data include the U.S. Census Bureau, Bureau of Land Management (BLM), International Boundary Commission (IBC) for the Canadian boundary, and the International Boundary and Water Commission (IBWC) for the Mexican boundary. Boundaries include city, county, State, Federal lands, provinces, and...
GIS map of United States
Geographically (and as a general reference), the United States of America includes all areas considered to be under the sovereignty of the United States, but does not include leased areas. On May 14, 1959, the U.S. Board on Geographic Names issued the following definitions based partially on the Alaska Omnibus Bill, which defined the Continental...
U. S. Board On Geographic Names
Federal, state, local, and non-governmental data partners continuously submit new features and edit existing features in the Geographic Names Information System (GNIS) database. Changes--potentially consisting of hundreds to thousands of records per month--are validated by the staff and made available on the GNIS website and in the Web services....
GIS data layers visualization
The Geographic Names Information System (GNIS) was developed by the U.S.Geological Survey (USGS) in cooperation with the U.S. Board on Geographic Names (BGN), which maintains cooperative working relationships with state names authorities to standardize geographic names. GNIS contains information about the official names for places, features, and...
small excerpt of Yosemite Valley topographic map in shades of green and brown
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...
Multi-temporal Landsat NDVI (Normalized Difference Vegetation Index) product overlaid on aerial photographs
The Spectral Characteristics Viewer is an interactive tool that can be used to visualize how the bands--or channels--of different satellite sensors measure the intensity of the many wavelengths (colors) of light. This is also known as the relative spectral response (RSR). By overlaying the spectral curves from different features (spectra), one can...