The impact of the ?skeleton? and ?skin? for the streetscape on the walking behavior in 3D vertical cities

To reconcile the conflict between urban population agglomeration and spatial resource constraints, some cities are continuously expanding their space to high altitudes, gradually changing human activity behavior at the same time. Most of the literature analyzing the walking environment based on a two-dimensional (2D) plane may generate a significant deviation in portraying real-world urban scenes. The paper contributes to the literature by providing the ???skeleton??? and ???skin??? measurements to portray spatial geometric structures and the elements of visual surface for streetscapes in real-world urban scenes. Furthermore, this study fills the research gap in how three dimensional (3D) vertical landscapes influence walking behaviors for commuting and noncommuting purposes. The findings reveal that the strong enclosure skeleton of the street may inhibit walking behavior by creating a sense of oppression, while green, blue, and diverse skin for the streetscapes facilitates resident participation in noncommuting walking. This paper calls on planners to create more public spaces with human -oriented size and natural landscapes beside streets to achieve a pedestrian-friendly 3D vertical city.