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Digital Raster Graphics (DRGs)

   

    1:24,000 Scale DRG
    (Eastford, CT)

   

    1:250,000 Scale DRG
    (Hartford, CT)

A Digital Raster Graphic (DRG) is a scanned image of a USGS standard series topographic map, including all map collar information. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator (UTM) projection. The horizontal positional accuracy and datum of the DRG matches the accuracy and datum of the source map. The map is scanned at a minimum resolution of 250 dots per inch.

DRGs have been made for all quadrangles in the USGS standard topographic map series for the United States, its territories and trusts. Source maps include:

  • 7.5-minute maps of the conterminous United States, Hawaii, and limited areas of Alaska at 1:24,000 and 1:25,000 scale.
  • 7.5 by 15-minute maps in limited areas of the conterminous United States at 1:25,000 scale.
  • Pacific Island maps at 1:20,000, 1:24,000, and 1:25,000 scales.
  • Puerto Rico and the Virgin Islands at 1:20,000 scale.
  • Culebra, its adjacent islands, and the Island of Vieques at 1:30,000 scale.
  • Alaska at 1:63,360 scale.
  • 30 by 60-minute maps of the conterminous United States at 1:100,000 scale.
  • 1 by 2-degree maps of the United States at 1:250,000 scale.

DRGs are in TIFF 6.0 and use GeoTIFF 0.2 specifications to define a set of TIFF tags. These tags describe all cartographic information associated with the file. The average file size is 10 megabytes.

Additional Information

Data Use and Citation Policies

For information on how to cite USGS data plus guidance on usage restrictions,
please see our Data Citations and Use page at https://lta.cr.usgs.gov/citation.

Contact Information for User Assistance

Long Term Archive User Services
U.S. Geological Survey (USGS)
Earth Resources Observation and Science (EROS) Center
47914 252nd Street
Sioux Falls, SD 57198-0001

Phone Number: 605-594-6151
Toll Free: 800-252-4547
Fax: 605-594-6589

Email:lta@usgs.gov
Web: https://lta.cr.usgs.gov

Business Hours: Monday thru Friday, 8:00 a.m. to 4:00 p.m., Central Time