Orthophoto
A geometrically corrected aerial or terrestrial photograph in which scale is uniform throughout, suitable for precise measurement — unlike a perspective photograph.
An orthophoto (or orthophotograph) is a photograph that has been geometrically corrected to remove the distortions of perspective — the foreshortening and scale variation that occur in a standard camera view because objects at different distances from the camera appear at different scales.
In photogrammetry, orthophotos are generated from the textured 3D model by projecting the surface texture onto a flat plane viewed from directly above (for a map-view orthophoto) or directly in front of an elevation (for an elevation orthophoto). The result is an image in which every point is at the same scale — a true 1:1 geometric representation that can be used for direct measurement.
Heritage orthophotos are used for elevation drawings, condition mapping, sculptural inventory and precise area calculations. A façade orthophoto of a historic building, exported at a specified scale, can be printed to any size and used as a drawing base.