Measurement of Comfort in Urban Landscape Using the Ratio of Vertical Green Coverage by Chromaticity

Interest in the ratio of vertical green coverage has increased now. This paper aims to quantify the psychological effects of the ratio of vertical green coverage and to clarify the relationship between the color environment and the ratio of vertical green coverage. In this study, 27 urban landscape images were presented as simulations to 26 subjects, and the change in psychological feelings was examined by various indexes. The images were analyzed by the chromaticity diagram CIE1976u’v’. The results were as follows. As the correlation between the ratio of vertical green coverage by attributes (for example, leaves, flowers, stems, and branches which were components of the plant) increased, the ratio of vertical green coverage by chromaticity was a more accurate indicator. In the ratio of vertical green coverage, Stevens’ power law was more effective in explaining the relationship between physical quantities and psychological evaluations. In a multiple regression analysis using opposite color components, the number of colors and the comfort evaluation, the regression equation using red, green and yellow components as the explanatory variables demonstrated the greatest explanatory power. The coefficients of this equation were -278 (red), +55 (green) and +47 (yellow). Therefore, in quiet residential areas and crowded city centers, the required level of the ratio of vertical green coverage may be different. Increasing the ratio of vertical green coverage can be expected to improve the color environment easily.