A method to estimate sky view factors from digital elevation models

Abstract

Sky view factor (SVF) is a commonly used parameter in atmospheric sciences. A method how to obtain an approximate value of SVF from digital elevation models (DEM) is described. The method takes into account slopes and transmittance of objects and is able to compute SVF for complex geometries (e.g. urban environments, natural landscapes, etc.). It is based on the concept of view factor, sometimes called 'form factor' or 'shape factor' in the literature. The view factors are computed between the calculation point and numeric sky dome to obtain an estimate of the final SVF value. A special procedure is applied to take limitation of sky visibility by obstacles into account. Accuracy of the method is checked by comparison with theoretical SVF values and tested on examples of complex geometries. © 2012 Royal Meteorological Society.