Examining the Relationship Between Enclosure Ratio of Street and Skyline’s Complexity

Abstract

Purpose The urban design criteria significantly affect the visual quality of space. Enclosure and Complexity can be defined as two crucial urban design principles that affect the perceptibility and visual quality of space. This study aimed to offer an objective and perceptual evaluation method in assessing the street’s enclosure ratio. In the study, the street's enclosure ratio was evaluated via the street skyline's complexity. Design/Methodology/Approach According to the study's hypothesis, as the street's enclosure ratio increases, the street skyline's complexity level decreases. For testing this hypothesis, the street images were selected from the London and Chicago cities. Firstly, the skylines of the streets were determined on images, and then, the fractal dimensions of skylines were calculated. Then, the street’s enclosure ratio and the factors that affect street skyline's fractal dimension were measured with a defined measurement system. Subsequently, the relationship between the street’s enclosure ratio and calculated street skyline's fractal dimensions was examined by regression analysis. Findings As a result, it was determined that there is an inverse relationship between the street’s enclosure ratio and the street skyline’s fractal dimensions. As the enclosure ratio increases, the complexity of the skyline decreases. The decrease in the complexity level of the skyline weakens the visual quality and perceptibility of the street. Research Limitations In this study, the perceptual evaluation of the street’s enclosure ratio was examined with an objective method. This method can also be reinforced with a subjective evaluation and more precise results can be obtained. Social Implications The obtained results can provide important clues to increase the visual quality and perceptibility of the streets. In perceptible spaces with high visual quality, feelings such as liking, trust, belonging and comfort develop in people. Originality/Value The fractal approach as an objective method is used widely for perceptual evaluation of the complexity level in cities. However, it was determined that very few studies examined the street’s enclosure ratio with the perceptual and objective evaluation method. Perceptual evaluations of the enclosure were generally made with subjective methods. This study offered an objective and perceptual evaluation approach for examining the street’s enclosure ratio.