Digital Orthophotographs

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Digital orthophoto quads are computer-readable air photos that have been processed to minimize distortions found on traditional photos. When these products are formatted to correspond with quadrangle maps, they are called digital orthophoto quadrangles. Minnesota was the second state in the nation to complete statewide coverage. 

Black and white DOQs for the entire state were completed by the U.S. Geological Survey from the 1991-92 NAPP flight. Each uncompressed quarter-quad data file covers about 13 square miles in Minnesota and is approximately 45 megabytes in size. These files can be obtained from USGS; however, most users would likely use the compressed county CDs. 

The thumbnail image above shows the State Capitol in the northern portion of downtown St. Paul. The full image is at 640x480 with a resolution of 1 pixel = 1 meter and shows the Capitol mall area, including the State Office, Transportation, Judicial and Centennial Office buildings. This and other digital orthophoto quads are best viewed with a monitor that can display images at 800x600 with 256 colors.

• Data error corrected: Replacement files available for data problems in west-central Minnesota.
• DOQ guide: LMIC's guide to locating digital orthophoto quarter quadrangle files.
• Map showing the most likely year of the source photos used to create the 1991-92 USGS DOQs.
• USGS national DOQ program
• USGS DOQ factsheet
• Ordering DOQ products

Related Sites

• 2003-04 orthophotos from the Farm Service Agency are available statewide; 2002 orthophotos are available for 28 southern Minnesota counties
• Metropolitan Council's 2000 DOQs and 1997 DOQs for the seven-county Twin Cities metropolitan area
• View and download nationwide DOQ images from Terraserver
• Download Minnesota DOQs from DNR:  resampled to 3 meter pixels and combined into full quadrangles
• Download Minnesota DOQs from LMIC:  resampled to 10 meter pixels and combined into county files
• Minnesota DNR's ArcView Resources: download custom applications for using DOQs with ArcView