Visualisation of DSM as 3D-mesh for urban analyses

Abstract

The study focuses on the application of the Digital Surface Model (DSM) for the visualisation of a city and urban analyses. The DSM is a cloud of points on a regular mesh derived from the airborne scanning (ALS/LiDAR). The accessibility of data is growing and the production cost decreasing. The current scanning precision is sufficient to present buildings including architectural details in the scale needed for urban analyses. Although the DSM can be easily presented at the cloud of points, it is insufficient to make full visualisation of a city and a number of urban analyses. To this end, it is necessary to be able to examine visibility while taking into consideration that facilities may obstruct each other views. In this context, the paper introduces a method of geometric representation and computation of DSM as full 3D-mesh. Key issue is the huge size of such a model, which is a challenge for processing. Results possible to achieve are discussed and they are compared with other types of models (like CityGML, reality-mesh-models). The research was implemented based on software (C++) developed by author. It enables to process areas of the city up to 180 km2 in DSM resolution (50 cm grid) for the purpose of urban visualisation and various urban analyses.