Abstract (eng)
In this work, the requirements for Digital Surface Models (DSM) as well as their acquisition methods for a GIS-based shadow simulation along a bicycle route in the rural area of the northern Waldviertel in Lower Austria were investigated. On the one hand, already available Digital Surface Models from public sources were used. On the other hand, an own DSM was created from UAV (unmanned aerial vehicle) surveys and SfM (Structure from Motion) methods for three sections of the bike route. For the former, a DSM from an image matching procedure based on aerial photography and a total of three DSMs from an airborne laser scanning survey with different spatial resolutions were examined. The objective was to determine if accurate shadow modeling could be accomplished using available models from airborne data collection and to what degree superior outcomes might be obtained with a DSM from UAV data acquisition. Shadow modeling was performed using the Solar Radiation tool in ArcGIS Pro. Regarding the requirements of the digital surface models for precise shadow simulation, it was found that a spatial resolution of at least 5 m is necessary regardless of the acquisition method to perform useful shadow modeling along the bike route. The best results were obtained using the SfM-UAV DSM due to the high resolution and timeliness of the data. However, when compared to the various DSMs already available, the added value of an UAV survey must be weighed, as the results of the SfM DSM are only slightly better. Comparing the DSMs from public sources, the model generated from airborne laser scanning with a resolution of 1 m provided the best results.