High-accuracy applications of the Microsoft Vexcel Ultracam_D large-format digital aerial mapping camera are discussed. Calibration results from 10cm ground sample distance (GSD) imagery are presented along with project results from surveys flown at 3.5cm GSD. These results approach the accuracy achievable by ground surveying methods.
These results show that aerial photogrammetry is not just a tool for topographic mapping or engineering planning purposes, it is also a tool for engineering design studies relating to such activities as rail and road construction.
The photogrammetric method allows quantifiable assessment of results, a permanent photographic record of the site, the ability to digitize vector data such as breaklines and hard edges in 3D stereo view as well as a dense DTM point distribution.