Three-dimensional Modelling of Breaklines from Airborne Laser Scanner Data

Airborne laserscanning allows a very detailed sampling of the landscape within a more or less automated recording procedure. For the representation of models computed on the basis of this data mostly raster or triangulated irregular networks (TINs) are used, which do only implicitly store breakline information. For high quality surface modelling breaklines must be explicitly stored within the data structure. Therefore a 3D vector representation of the breaklines is necessary. This paper presents a method for the modelling of 3D breaklines not only from airborne laser scanner data but from any kind of point cloud data. The method is based on a pairwise intersection of robustly estimated surface elements along the breakline. It allows a modelling on the basis of original irregular distributed point clouds even in wooded areas. For this procedure a 2D approximation of the breakline is required. Therefore one section concentrates on the determination of these initial values in order to automate the process. Results of the modelling are presented in an examples section. A summary with an outlook on future developments concludes the paper.