A new software tool for SVF calculations using building and tree-crown databases

This paper presents some results related to the development of an automatic evaluation method locating tree-crowns and building roofs, as well as a new method for Sky View Factor (SVF) calculation using tree-crown and building database. For the software based calculation of the SVF a detailed building and vegetation database is needed. In most of the urban areas some kind of urban building database is available, however there is a lack of detailed information related to the tree-crown data in general. The vegetation, and especially the tree-crowns are crucial parts of the urban 3D geometrical configuration, and they play a notable role in the regulation of long-wave radiation heat loss. Therefore in urban climate investigations a new method could be very useful in the evaluation of this kind of information. The automatic tree-crown and building database generation uses digital photogrammetric methods for tree height measurement and spectral information from aerial photographs. Using the generated tree-crown and building databases we can calculate the SVF pattern of any given urban area. Additionally, this calculation is fast and it is as precise as any vector based calculation method.