An orthophoto is an aerial photograph that has been geometrically corrected or 'ortho-rectified' such that the scale of the photograph is uniform and utilised in the same manner as a map.
An orthophoto is an aerial image that has been geometrically corrected (ortho-rectified) so that the image is uniform from edge to edge.
Orthophotos are corrected to eliminate terrain effects and distortions produced by camera sensors.
Orthophotographs are commonly used in Geographic Information Systems (GIS) as
base maps or background images on which other layers of data are superimposed.
A digital terrain model is added as a means of collecting ground points to indicate the elevation changes. When control points are identified on the aerial photos, stereo models are developed and geometric distortions are estimated. The image is rectified and georeferenced using mathematical models of photogrammetry to remove tilt, terrain, atmospheric and other digital image distortions.