What sources of vector data were used to create base maps in The National Map?

Vector data for small scales are from The National Map Small-Scale Collection, while medium to large scales are comprised of The National Map themes, including the National Hydrography Dataset (NHD) and Geographic Names Information System (GNIS) data. Other medium-to-large-scale vector features are from USGS edited versions of the U.S. Census Bureau's TIGER/Line data for Governmental Unit Boundaries, Structures, and Transportation.

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

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

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Updated 2015 version of Tupelo, Mississippi US Topo quadrangle with orthoimage turned on

How often are The National Map's composite base maps and dynamic service overlays updated? How often are The National Map's composite base maps and dynamic service overlays updated?

Composite base maps are recached about once a year. Although data in dynamic service overlays are ideally updated quarterly, it can sometimes take up to six months. Please note that there will be times when composite base maps and dynamic service overlays are not in synchronization because of a difference in refresh cycles. Subscribe to the National Map Simple Notifcation Service (SNS) to stay in...

How often are The National Map's composite base maps and dynamic service overlays updated?

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What are the base map services (or URLs) used in The National Map? What are the base map services (or URLs) used in The National Map?

The National Map Services offers a series of composite base maps that combine layers into tile cache services with the cartographic richness of multiple data sources. The following base maps are available: USGS Topo - combines the most current data (boundaries, geographic names, transportation, elevation, hydrography, land cover, and other themes) that make up The National Map. Contours generated...

What are the base map services (or URLs) used in The National Map?

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June 3, 2019

The National Map—New data delivery homepage, advanced viewer, lidar visualization The National Map—New data delivery homepage, advanced viewer, lidar visualization

As one of the cornerstones of the U.S. Geological Survey’s (USGS) National Geospatial Program, The National Map is a collaborative effort among the USGS and other Federal, State, and local partners to improve and deliver topographic information for the Nation. The National Map is featuring direct links to new and improved GIS data access utilities on a refreshed data delivery homepage at...

Authors

National Geospatial Program, 3D Elevation Program, The National Map - Data Delivery

June 23, 2017

Scanning and georeferencing historical USGS quadrangles Scanning and georeferencing historical USGS quadrangles

The U.S. Geological Survey (USGS) National Geospatial Program is scanning published USGS 1:250,000-scale and larger topographic maps printed between 1884, the inception of the topographic mapping program, and 2006. The goal of this project, which began publishing the Historical Topographic Map Collection in 2011, is to provide access to a digital repository of USGS topographic maps that...

Authors

Kristin A. Fishburn, Larry R. Davis, Gregory J. Allord

National Geospatial Program

January 1, 2005

Topographic map symbols Topographic map symbols

Interpreting the colored lines, areas, and other symbols is the first step in using topographic maps. Features are shown as points, lines, or areas, depending on their size and extent. For example, individual houses may be shown as small black squares. For larger buildings, the actual shapes are mapped. In densely built-up areas, most individual buildings are omitted and an area tint is...

Authors

Water Resources Division U.S. Geological Survey

January 1, 1993

Map projections Map projections

A map projection is used to portray all or part of the round Earth on a flat surface. This cannot be done without some distortion. Every projection has its own set of advantages and disadvantages. There is no "best" projection. The mapmaker must select the one best suited to the needs, reducing distortion of the most important features. Mapmakers and mathematicians have devised almost...

Authors

Water Resources Division U.S. Geological Survey

Core Science Systems Mission Area, Science Analytics and Synthesis (SAS) Program

Updated Date: June 26, 2025

What sources of vector data were used to create base maps in The National Map?

Related

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

How often are The National Map's composite base maps and dynamic service overlays updated?

What are the base map services (or URLs) used in The National Map?

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

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

USGS Topo Base Map Refreshed and Other Updates

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

How often are The National Map's composite base maps and dynamic service overlays updated?

What are the base map services (or URLs) used in The National Map?

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

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

USGS Topo Base Map Refreshed and Other Updates

Mapping Public Lands in the United States