Aerial photographs are generally classified as being vertical or oblique. A vertical photograph is one which has been taken with the camera axis directed toward the ground as vertically as possible, while an oblique photograph is one which has been taken with the camera axis directed at an inclination to the ground.
Aerial photography is the taking of photographs of the ground from an elevated/direct-down position. Usually the camera is not supported by a ground-based structure. Aerial photography - Wikipedia, the free encyclopedia