Comparison methods of terrestrial laser scanning, photogrammetry and tacheometry data for recording of cultural heritage buildings

Cultural heritage documentation projects very often combine different acquisition methods as tacheometry, photogrammetry and terrestrial laser scanning. In this paper we compare these three methods for recording of heritage buildings. Our test object is the medieval castle of Haut-Andlau (Alsace, France), documented in 2006-2008. This castle is of particular interest for our investigations since its architecture is the result of different construction styles completed over the centuries. Old buildings are rarely regularly shaped and most of their facades are made of very complex curved structures. The documentation of the castle became a true challenge, regarding the constraints implied on the one hand by the steep and abrupt terrain surrounding the castle and on the other hand by the dense and broadening vegetation close to the castle. It became rapidly obvious that a unique technique would not overcome the vegetation and relief obstacles. The main part of the data capture was based on TLS. For completion of the laser scanner data at occluded building parts and for accuracy assessment, stereoscopic as well as multi-image models have been captured. Advantages and disadvantages of the different methods will be discussed in this paper. A quality assessment leads to the analysis of the models derived from each technique and to a crucial experience for further campaigns.