Comparative study of different cartographic sources for viewshed generation

Abstract

The arrangement of the landscape significantly influences the visual experience of the environment. Viewshed calculation can play an important role in urban and natural resource planning. The Landscape Policy of the Valencian Community (Spain) is based on the European Landscape Convention, in which viewshed generation is an important part of landscape studies, often required for urban planning actions and environmental impact studies. The aim of this study was to compare different cartographic sources to identify which gives better results (closest to reality) referring to viewsheds generation. The cartographic sources used were: LiDAR (Light Detection And Ranging), ICV (Valencian Cartographic Institute) cartography and Gandia¿s Council cartography. Using a Geographical Information System (GIS), the data were processed to get their Digital Terrain Models (DTM). Combining these DTMs with the heights from the Cadastre and LiDAR, the Digital Surface Models (DSM) were obtained, allowing the calculation of each final viewshed. The results show that, the viewsheds derived from the LiDAR heights are the most accurate. The most inaccurate viewsheds are those that used the Cadastral data; however, these data are not entirely incorrect (average accuracy of 66%), therefore, the use of one source or another will depend on the precision required for possible future landscape studies.