What is Aerial Triangulation in Aerial Photogrammetry ?

Aerial Triangulation in Photogrammetry is methods of determine and calculate 3-dimensional object coordinates by photogrammetric means, by using photographs exposed from different positions, covering the same object.

With aerial triangulation in aerial photogrammetry we might be able to calculate 3-dimensional coordinates for object elements on almost any object. We need at least some points with known position that are visible in at least some of the photographs. These points we call ground control points, or any control points, the control points have to be a part of the aerial triangulation.

Why we are using aerial trangulation?

Usually it is more expensive to have people working out in the field, and it is also harder work than what it is to do the work is an office. Because of that different method has been developed to be able to reference a model with as few ground control points as possible. Still we need at least five  control points inside each aerial photogrammetry model to be able to do an absolute orientation of the model.

In aerial photogrammetry,to be able to get that many points a method named aerial triangulation is developed. This method is that we measure several unknown point clearly visible in the aerial triangulation in a stereo instrument. These new points together with the ground control points and the exposures positions for the camera are put together in a big computation. The result we get out of this is the coordinates in the reference system for all the new measured points.

What are the inputs for aerial triangulation?

1.    Scanned Images
2.    Camera Report
3.    Ground Control Data/ Ground Control Point