A Method for Identifying Consistent Streetscape Skeletons in Terms of Building Heights and Setbacks: From a Pedestrian’s Perspective Based on the Neighbourhood Relations of Buildings Forming 3D Streetscapes

Abstract When identifying buildings constituting consistent streetscape skeletons with small differences in the heights and setbacks, we face the following challenges from a pedestrian’s perspective: (1) how to precisely define the spatial extent of streetscape skeletons; and (2) how to identify consistent 3D streetscape skeletons. Although methods have been developed for quantifying the degree of difference between the heights and setbacks of adjacent buildings on a 2D map, called the relative spatial variability in building heights and setbacks, the relative spatial variability in streetscape skeletons forming a 3D streetscape is yet to be quantified. This is because the neighbourhood relations among buildings composing 3D streetscape skeletons, based on what a pedestrian sees on the street, remain unclear. To address these issues, when buildings composing a 3D streetscape at a location on the street centreline are projected onto the virtual screen, vertical to the ground, and street centreline, they are regarded as being adjacent to one another on the screen, which is the neighbourhood relations in terms of 3D streetscape composition . This study thus aims (1) to develop a method for visualising this neighbourhood relation on a 2D map; and (2) to identify consistent streetscape skeletons from a pedestrian’s perspective based on a new local indicator of spatial association considering this neighbourhood relation. The method can help urban planners evaluate the effectiveness of policies for maintaining consistent streetscape skeletons by identifying where buildings forming consistent or inconsistent 3D streetscape skeletons are spatially clustered from a pedestrian’s perspective via a 2D map.