Modeling urban intersection form:Measurements,patterns,and distributions

Intersections appear where one street crosses another,acting as fundamental nodes embedded in the network of urban public space.Though discussed in configurational and perceptive studies,limited attention has been paid to the morphological aspects of inter-sections.This study proposes and tested a new approach to modeling the urban intersection form.First,effective cylinder was introduced to define the related space for each intersection based on its scale.Second,a set of morphological indicators were presented to measure the physical properties of the intersection form.Third,the affinity propagation algorithm was used to examine the patterns of intersection form.Using the Old City of Nanjing,China as the study area,844 intersections were analyzed to test this new method.As a result,we were able to classify the intersections into eight types.This study shows that the intersection can be modelled as a volumetric and integral spatial unit of urban form,which may demand more attention from urban designers and architects in the future for shaping the built environment.The quantitative nature of our method could also open more possibilities for intersection-based studies.