Orthorectification is the process of removing the distortion within an image caused by terrain relief and the camera. This is done by modeling the nature and magnitude of geometric distortions in the imagery. Camera or satellite models in conjunction with limited ground control, allow construction of correction formulae that produce accurate, geometrically correct, map-oriented imagery. Geoascent and partners uses Leica Photogrammetric Suite to produce orthoimages.
Orthorectification is also usually required if several images or scenes need to be mosaiced in order to ensure that the joins are seamless. For both rectification and orthorectification, accurate ground control is essential to produce geometrically accurate imagery. Geoascent and partners also provides options of Seamless mosaicing of large detests for a visually appealing image.