Airborne lidar data as a base for the open space 3D model construction

Abstract

Digital elevation models (DEM) provide basic information on heights of the Earth’s surface and objects upon it. The specific terms Digital Terrain Model (DTM) and Digital Surface Model (DSM) are often used to specify the surface objects described by an elevation model. A DTM usually refers the physical surface of the Earth, when a DSM describes the upper surface of the landscape. In any case, a digital elevation model is the interface between the Earth’s surface and the air. When modelling the interface to the air, we would like to introduce a kind of DSM– Open Space 3D Model, which is restricted by a surface generated over the physical Earth’s surface, natural and artificial objects, and in which the distances between the rough elements of this surface are not less than a given critical tolerance. In other words we have in mind the moving objects of the certain dimensions, which could freely move in such open space. The open space surface is similar to a digital surface model, therefore in general it is more smoother. The technological peculiarities of an open space 3D model generation are analysed. The two main sources of data were suggested to apply: the raw airborne LiDAR data and the orthophotomaps. The method for generation of an open space surface is presented too. An open space 3D model on experimental territory was generated. The data of single orthophotomap at a scale of 1:10, 000 (5×5 km) was applied. The comparisons against digital terrain model and digital surface model are given.