Summary

An orthophoto is generated from aerial photographs that have been rectified to adapt to the shape of the terrain, so that the camera's point of view does not affect the real position of objects.

Definitions

Aerial photography

A photograph of a part of the earth's surface taken using the aerial photography technique with the aim of obtaining information or measurements of geographical entities, for cartographic purposes and measurement analysis.

An aerial photograph is a perspective projection of an area of ​​the terrain from an elevated projection center, so that the points are displaced and have a decreasing scale from the nadir. Depending on the relationship between the camera station and the scene, the aerial photograph can be vertical, oblique or horizontal.

Orthophoto

A photograph with constant scale and properties of an orthogonal projection, formed from a central projection photograph by differential rectification.

In an orthophotograph, objects occupy their true horizontal positions. If the rectification has been analog, the displacement of the vertical surfaces has not been corrected.