orthophotos are geographically and geometrically corrected aerial
Aerial Photography uses KLT Atlas softcopy analytical stereo plotters
for orthophoto production.
are scanned using a Vexcel 5000 photogrammetric scanner. These scanners
provide pixel accuracy of +/- 2 microns.
process of ortho rectification incorporates:
Aerotriangulation, which provide the position and attitude of the
camera at exposure(2) Surface elevation model (or Digital Terrain
(3) Scanned imagery
pixel resolutions for these images are .5 foot for 1"=100'
final scale maps and 1 foot for 1"=200' final scale map.
orthophotos provide an image backdrop in GIS / mapping applications.
The information these images provided is a perfect supplement to
traditional map data.
The orthophoto process applies photogrammetric methods to eliminate
distortions errors found in traditional aerial photography. These
distortions are present in aerial photography that has not been
ortho rectified. A number of distortion factors including the camera
lens, camera tip and tilt, ground surface relief and radial feature
displacement from the photo center.