| Digital Raster GraphicsScanned and registered images of USGS quadrangles 
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Digital raster graphic (DRG) files are 
  being redistributed through this Web site as a service to program partners of 
  the Upper Midwest Environmental Sciences Center. The 1:24,000-scale DRG files 
  for the Upper Mississippi River floodplain have been modified, their maps collars 
  have been removed and a buffer strip of neighboring quadrangle data added to the 
  images. These modifications were performed to make it easier for users to create 
  mosaic images from several images. If you require these data in their original 
  format, contact the EROS 
  Data Center.
  
For more information on digital raster graphics including a 
  listing of Web sites that distribute DRG files through the Internet, contact the Mid-continent Mapping Center in 
  Rolla, Missouri.  
 
		 
			