Does a physical geographer need millions? Experience with terrestrial laser scanning in geographical survey

In this paper, we present our experience with terrestrial laser scanning (TSL) in geographical filed-survey. This technique provides extremely accurate 3D model of given object or locality, which consists of millions points (so-called point cloud); each of them is determined by X, Y and Z coordinates. However, usability of this large amount of points fundamentally depends on researcher's requirements (i.e. on the type of required output) as well as on the conditions in the field. For example, if one needs to create accurate digital terrain model of small area with dense vegetation, only few points may be usable for final interpolation of digital terrain model. As dense vegetation has to be filtered out, data pre-processing becomes technically more demanding and more time-consuming and accuracy of final model necessarily decreases. For these reasons, we emphasize that, in geographical survey, TSL is the most effective for modelling of small geomorphological objects and landforms which are not covered by vegetation and also for making profiles and cuts. This should be taken into consideration when the filed-survey is prepared