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CR 42:177-183 (2010)  -  DOI:

Continuous sky view factor maps from high resolution urban digital elevation models

F. Lindberg*, C. S. B. Grimmond

Environmental Monitoring and Modelling Group, Department of Geography, King’s College London, London WC2R 2LS, UK

ABSTRACT: This paper presents a new method to calculate sky view factors (SVFs) from high resolution urban digital elevation models using a shadow casting algorithm. By utilizing weighted annuli to derive SVF from hemispherical images, the distance light source positions can be predefined and uniformly spread over the whole hemisphere, whereas another method applies a random set of light source positions with a cosine-weighted distribution of sun altitude angles. The 2 methods have similar results based on a large number of SVF images. However, when comparing variations at pixel level between an image generated using the new method presented in this paper with the image from the random method, anisotropic patterns occur. The absolute mean difference between the 2 methods is 0.002 ranging up to 0.040. The maximum difference can be as much as 0.122. Since SVF is a geometrically derived parameter, the anisotropic errors created by the random method must be considered as significant.

KEY WORDS: Urban climate · Urban geometry · Urban surface parameters · Geographical Information Systems · Sky view factor · London

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Cite this article as: Lindberg F, Grimmond CSB (2010) Continuous sky view factor maps from high resolution urban digital elevation models. Clim Res 42:177-183.

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