A Digital Raster Graphic (DRG) is a digital image (scanned version) of
the USGS topographic map. DRGs are produced from USGS 1:24,000-, 1:24,000/1:25,000-,
1:63,360- (Alaska), 1:100,000-, and 1:250,000-scale topographic map series.
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.
A DRG may be used as a source or background layer in a geographic information
system (GIS) to collect, review, and revise other digital data. A DRG
can be combined with a DEM and a DOQ to produce an image with additional
visual information for the extraction and revision of base cartographic
To learn more about DRGs, check out the
at the Crater Lake Data Clearinghouse Web site.
The San Francisquito Creek project covers six USGS 7.5-minute quadrangles.
These six quads have been mosaicked together for your convenience of viewing
and analyzing the information throughout the area. Data are reprojected
to one standard projection (UTM NAD27 zone 10 meters). Click on
the following link to download the data:
drg100k.zip (4 MB uncompressed)
-- DRG with world file in TIFF format.
MB uncompressed) -- DRG with world file in TIFF format.
drg24k.zip (20 MB uncompressed)
-- DRG with world file in Mr. SID format.
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