Computation of the greenery-sky-view factor in daylit buildings

The greenery-view factor has been recently proposed as a new, simple measure to assess the possibility of having visual access to view the outdoor greenery in a daylit building space, based on the constructed lines of sight. However, detailed expressions to compute the factor is yet to be provided, and correlations with the input variables are yet to be determined. This study aims to address those issues, by combining the 'no-greenery line' with the 'no-sky line' to create the greenery-sky-view factor (GSVF), which is the fraction of the floor area, at the eye-level height, from which the greenery and the sky are visible. Mathematical expressions to compute the GSVF are described for various scenarios involving the window-to-wall ratio, the elevation of the greenery, and the distance between the window and the greenery. Computations of 10,000 random combinations are performed to find the optimum input variables leading to the largest GSVF and to determine correlations between the input and output. Recommendations for design practice are provided based on the computation results.