Digital Ortho Quarter Quads (DOQQs)

(USA only)

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1m pan (gray-scale) or CIR (color infra-red) ortho-rectified aerial photography. Near full-coverage for the continental US, majority coverage for Puerto Rico, limited coverage of Alaska (satellite imagery available for other areas). Rapid delivery and below-USGS pricing.

Digital Ortho Quarter Quads (DOQQs) are created by scanning an aerial photograph. Using a scanning aperture size of about 25 microns (about one-third the diameter of a human hair), the computer digitally compares the raster image with the corresponding Digital Elevation Model (DEM) to mathematically adjust the image, pixel by pixel. This is a fast and effective way to eliminate ground displacement caused by airplane tilt and the perspective view of the photograph- that is, the camera is not being directly over every object in the photograph.

Each DOQQ covers an area of 3.75 minutes of latitude by 3.75 minutes of longitude (roughly four miles by four miles). The imagery is geo-referenced so that other digital map layers can be overlayed on it, and the data meets 1:12,000 NMAS (National Map Accuracy Standards, equivalent to 10m CE 90).

DOQQs have between 50 and 300 meters of over-edge, sufficient for mosaicing after re-projection. LAND INFO offers a variety of value-added DOQQ processing such as re-projection, CIR to natural color simulation, CIR to pan conversion, tonal balancing, mosaic output and compression.

1m pan (gray-scale) or CIR ortho-rectified aerial photography example

File Formats
  • TIFF with TFW
  • GeoTIFF
  • ERS (ER Mapper)
  • MIF (Map Info)
  • JPEG 2000
  • JPEG with JPW
  • Generic Binary
  • Img (ERDAS)
  • ECW (ER Mapper, compressed)
  • MrSid (compressed)

Delivery Options
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LAND INFO provides several different delivery options:
  • FTP
  • CD-ROM
  • External Firewire/USB 2 Hard Drive