Terms and Definitions 

Orthorectification: the process of removing errors from an aerial photograph caused by lens distortion, camera tilt, varying distance to camera, etc. Typically requires a number of known "control points" on the ground that can be correlated with features on the photograph.

Photogrammetry: Measurement of an object from a photograph. In the context of orienteering maps, this usually refers to the creation of a base map from aerial photos.

GIS data formats