Quantifying Urban Form: Compactness versus 'Sprawl'

TLDR

Past research on urban form, compactness, and sprawl and their quantitative variables is reviewed and analyzed. The study develops quantitative variables to characterize metropolitan urban forms and distinguish compactness from sprawl. Four variables—metropolitan size, activity intensity, distribution evenness, and clustering of high‑density sub‑areas—are defined and evaluated via simulations using the global Moran coefficient to differentiate compactness from sprawl. The Moran coefficient is high for monocentric, intermediate for polycentric, near zero for decentralised sprawling forms, and decreases further with increased local sprawl such as discontinuity and strip development.

Abstract

This paper develops a set of quantitative variables to characterise urban forms at the metropolitan level and, in particular, to distinguish compactness from 'sprawl'. It first reviews and analyses past research on the definitions of urban form, compactness and sprawl, and corresponding quantitative variables. Four quantitative variables are developed to measure four dimensions of urban form at the metropolitan level: metropolitan size, activity intensity, the degree that activities are evenly distributed, and the extent that high-density sub-areas are clustered. Through a series of simulation analyses, the global Moran coefficient, which characterises the fourth dimension, distinguishes compactness from sprawl. It is high, intermediate and close to zero for monocentric, polycentric and decentralised sprawling forms respectively. In addition, the more there is more local sprawl, composed of discontinuity and strip development, the lower is the Moran coefficient.