Digital Raster Graphics (DRG's) Contents: Description Specifications Format Information Download Information

24K DRG subset image (Annapolis MD)

Description

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 most of the 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 x 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 x 60-minute maps of the conterminous United States at 1:100,000-scale.
* 1 x 2-degree maps of the United States at 1:250,000-scale.

The source data consist of the original USGS DRG's, but have been made available as a collarless seamless product. To see the areas where the seamless product is available, at the map interface, open the Layer Index group, then click on the DRG 24K Coverage, 100K, or 250K Coverage Index.

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Specifications

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Format Information

TIFF with world file, includes a projection file.

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Download Information

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