A digital raster graphic (DRG) is a scanned image of a U.S. Geological Survey (USGS) standard series topographic map, including all map collar information. The image inside the map neatline is georeferenced and fit to the Universal Transverse Mercator 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. Read the full USGS description online. Dates for all the DRG's at this site is included in the Alphabetical List of the 1:24,000 Quads.
Data made available by the Virginia Dept of Mines Minerals and Energy.
The following DRG Data files are available from the Reference Dept.'s GIS server:
Sun: Open 9:00am*
Mon-Thu: Open 24 hours*
Fri: Close at 8:00pm*
Sat: 9:00am - 8:00pm
* During 24 hour operation, a valid Hokie Passport is required to access or remain in the library between 12 midnight and 7:30am.