IMT Atlantique - IMT Atlantique Bretagne-Pays de la Loire (Campus Brest : Technopôle Brest-Iroise CS 8381829238 BREST Cedex 3 -
Campus Nantes : 4, rue Alfred Kastler- La chantrerie 44300 NANTES -
Campus Rennes : 2 Rue de la Châtaigneraie, 35510 CESSON SEVIGNE - France)
Abstract : The sky view factor (SVF) has an important role in the analysis of the urban micro-climate. A new vector-based SVF calculation tool was implemented in a free and open source Geographic Information System named OrbisGIS. Its accuracy and computational performance are compared to the ones of an existing raster based algorithm used in SAGA-GIS. The study is performed on 72 urban blocks selected within the Paris commune territory. This sample has been chosen to represent the heterogeneity of nine of the ten Local Climate Zone built types. The effect of the algorithms' input parameters (ray length, number of directions and grid resolution) is investigated. The combination minimizing the computation time and the SVF error is identified for SAGA-GIS and OrbisGIS algorithms. In both cases, the standard deviation of the block mean SVF estimate is about 0.03. A simple linear relationship having a high determination coefficient is also established between block mean SVF and the facade density fraction, confirming the results of previous research. This formula and the optimized combinations for the OrbisGIS and the SAGA-GIS algorithms are finally used to calculate the SVF of every urban block of the Paris commune.
https://halshs.archives-ouvertes.fr/halshs-01831117
Contributor : Gwendall Petit
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Submitted on : Thursday, July 5, 2018 - 3:57:34 PM
Last modification on : Monday, February 25, 2019 - 3:14:16 PM
