Compact or disperse? Evolution patterns and coupling of urban land expansion and population distribution evolution of major cities in China, 1998-2018

In terms of both land and population, rapid urbanization has shaped and transformed the internal structure of cities. Despite the increasing number of studies on these two dimensions of urbanization, little attention has been paid to their spatiotemporal coupling or to the reflection of this phenomenon in public policy. Based on the various terms used to describe or quantify compactness or dispersion trends in both dimensions in the existing literature, this study aimed to establish a comprehensive scheme to avoid ambiguity and reveal the complexity of urbanization. Using gridded data for land and populations, this study explored urban compactness or dispersion from multiple dimensions, and quantified the spatiotemporal coupling of urban land expansion and population distribution evolution in 35 major Chinese cities, over the period 1998-2018. Results show the following: (1) population decentralization and land expansion consolidation have been prevalent over the past two decades; (2) small, scattered sub-centers in the suburbs have declined, whereas large sub-centers have been expanding; and (3) better coupling of both dimensions was detected in smaller cities, with more rapid and dispersed land expansion. The latter sites were located mostly in western provinces, which had more centralized, monocentric populations. These findings help reveal spatiotemporal divergences in policy implementation regarding the urbanization process, and offer a comprehensive review of urbanization stages, intra-city relations, and the intrinsic motivations behind urbanization.

Automated summary

Research has shown that over the past two decades, population decentralization and land expansion consolidation have been prevalent. Small, scattered sub-centers in the suburbs have declined while large sub-centers have expanded. Better coupling of both dimensions was detected in smaller cities with more rapid and dispersed land expansion.