Positional error modeling of sky‐view factor measurements within urban street canyons

Abstract The sky‐view factor (SVF) in the urban street canyon is a single point‐specific measurement that can only represent the ratio of the visible sky of a specific point. The positional error of the SVF observation point (PE‐SVFOP) to the measurement of the SVF for specific applications is often ignored. This study conducted a quantitative exploration of the positional error in SVF measurements (PE‐SVF) by comparing the SVF estimated at the desired SVF observation point and the corresponding actual SVF observation point. A numerical geometric‐based method was applied in urban street canyons with five typical aspect ratios to explore the effect of both the lateral and vertical positional error of SVF observation points on the measurement of SVF. An empirical case study using a simulation‐based method was then conducted with a 3D city model of a typical street canyon in Hong Kong. The empirical results show that the average and maximum PE‐SVFs were −0.0051 and 0.0181, respectively, and the average and maximum relative PE‐SVFs (RPE‐SVFs) were 7.68 and 20.37%, respectively. An open‐source toolbox was developed to evaluate the PE‐SVF and RPE‐SVF, which can assist specific SVF applications with a more comprehensive consideration of the PE‐SVF.