Topographic Maps

USGS Digital Raster Graphic Enhanced (DRGe)

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	Directory listing (alphabetical - .zip)
	Directory listing (hierarchical - .tgz)

DRG Basics

The Digital Raster Graphic (DRG) is a scanned, digital image of a US Geological Survey (USGS) standard series topographic map. The original DRG images included the full map extent and surrounding map collar information. To produce the DRGe product, the USGS removed map collars and appended portions of surrounding map images to create rectangular images which are suitable for seamless tiling in a geographic information system.

Our archive includes map images from the 7.5-minute series (1:24,000), the 30 x 60-minute series (1:100,000), and the 1 x 2 degree series (1:250,000).

ESRI ArcGIS Users

Building pyramids on a DRG may corrupt the color ramp associated with the TIFF and cause the image to be displayed without color. If this occurs, simply delete the pyramid file (extension .rrd) to view the image with an appropriate color ramp. If ArcGIS asks if you would like to build pyramids, select the No option.

File Format

Coordinate System: UTM, Zone 16 North
Horizontal Datum: NAD27 (both NAD27 and NAD83 worldfiles are included with archives)
File Format: GeoTiff (5-10 MB/File)