A digital raster graphic (DRG) is a scanned image of a U.S. Geological Survey (USGS) topographic map. The scanned image includes all map collar information. The image inside the map neatline is georeferenced to the surface of the Earth. The DRG can be used to collect, review, and revise other digital data, especially digital line graphs (DLG). When the DRG is combined with other digital products, such as digital orthophoto quadrangles (DOQ) or digital elevation models (DEM), the resulting image provides additional visual information for the extraction and revision of base cartographic information. The USGS is producing DRG's of the 1:24,000-, 1:24,000/1:25,000-, 1:63,360- (Alaska), 1:100,000-, and 1:250,000-scale topographic map series.
Digital Raster Graphic (DRG) Data Sources
The Midcontinent Mapping Center of the USGS at http://topomaps.usgs.gov/drg/ is the main distributor of DRG data. Scroll to the bottom of the page for DRG's on-line as well as ordering information.
Tools for Using Digital Raster Graphic Data
All tools below were compressed with PKZip.
Download DRG Tools Extension The DRG-Tools extension provides tools for edgematching (mosaicking) Digital Raster Graphic (DRG) scanned quad images created by the Teale Data Center (Teale), the Tennessee Valley Authority (TVA), and the United States Geological Survey (USGS). Other utilities are also provided, including options for isolating specific image features such as contours or hydrography. You must have ArcView version 3.0 or higher to use the extension. Documentation is included in the zipped file.
FWS DRG Clipping AML, was developed in Alaska and specific to that area, but it could be edited for other areas. It projects the DRG's from the UTM projection to Albers as part of the process. Documentation is included: questions should be directed to Jerry Minick , in the Division of Information Resources and Technology Management, at Jerry_Minick@fws.gov.
USGS DRG Clipping AML, which can be used with all scales DRG's nationwide. You will need to download the applications and related files separately, as some of the files are very large. You will need the AML's etc for all scales; you can download only the scale you are working with for the other files.
AML's, documentation, and compiled files. (65K)
Documentation in pdf format
List of 1:24,000 quads (1.1MB)
List of 1:25,000 quads ( 1.1MB)
List of 1:63,360 quads (302K)
Lists of 1:100,000 and 1:250,000 quads (42K)
For additional information regarding this Web page, contact Deb Southworth Green , in the Division of Information Resources and Technology Management, at Deb_Green@fws.gov
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Keywords=GIS, data, watersheds, huc, hydrologic, units
Last Modified January 03, 2001 08:42 AM