Digital OrthophotographyDigital Orthophotography
TOBIN's
Digital OrthoMaps®, or DOMs are created by scanning and rectifying aerial photography to
eliminate distortions due to the earth's curvature, topographic relief, lens imperfection
and flight conditions. During this process, the image is coupled with a Digital Elevation
Model resulting in an xyz-coded image. DOMs meet mapping accuracy standards of 1" =
500' (±10 ft). The image data is rigorously tied to photo-identifiable National Geodetic
Survey (NGS) ground control utilizing the required number of sub-meter accuracy Global
Positioning System (GPS) control points. A Digital Terrain Model (DTM) is generated from
ground control or stereo models to properly rectify the DOMs. This process produces a
final product with a three-foot pixel resolution and can be generated on the datum and
coordinate system requested by the client.
A lower resolution version, or Modified DOMs can be generated which meets a map accuracy standard equivalent to that of a U.S.G.S. 7.5-minute quad sheet (±40 ft), and results in data at six-foot pixel resolution delivered on the datum and coordinated system of choice. Every other frame of image data is scanned and rigorously tied to USGS 7.5 minute U.S.G.S. topo quad sheets. Modified DOMs work well in areas of flat terrain. In areas of rugged terrain, a DTM may be necessary to eliminate photographic distortion caused by the terrain.
TOBIN also has a large inventory of off-the-shelf digital orthophotos. Visit the Digital Orthophotography section under Data for a detailed availability listing.