What is aerial photogrammetery

Aerial photogrammetry is the process of preparing maps and plans form aerial photography.

Vertical aerial photographs are taken along a series of parallel passes called flight strips. Each successive photograph overlaps approximately 60% of the coverage of the previous photo along the flight strip. Two adjacent photographs taken this way are called a stereopair.

The digital stereopair of photos is brought into photogrammetric software where the camera positions and camera tilts are re-established. Using 3D glasses photogrammetrists prepare maps and plans and measure the 3 dimensional coordinates of all points of interest. These maps and plans provide an instantaneous snapshot of the area of interest and are especially useful in rapidly changing areas such as quarries, open cut mines and landfills as well as being able to survey large areas for infrastructure development and flood mapping relatively quickly and inexpensively.

The accuracy of measurements usually depends on flying height and the amount of ground control points. Accuracies of +/-0.1m may be achieved in 3 dimensions.