Measuring the spatial and size polycentricity: An empirical study of China's urban agglomerations using population distribution data

Abstract

The development of cities has distinguishing regional characteristics, which makes researchers and decision makers carry out studies and discussions on polycentricity. Current research quantifies morphological polycentricity from the perspective of the center's importance, ignoring their spatial distribution pattern. To fill this gap, this work attempts to provide a two-part framework that measures regional morphological polycentricity: (1) both spatial and size polycentricity are measured by center's influence sphere and standard deviation, respectively, to provide a comprehensive assessment of morphological polycentricity; (2) groups of regions with similar morphological features are identified through K-means clustering by combing spatial polycentricity, size polycentricity and three additional factors. To verify the effectiveness of the proposed framework, we conducted an empirical investigation in 20 Chinese urban agglomerations using the LandScan population distribution data. The findings validate the hypothesis that the distribution of centers cannot be fully characterized only from either spatial or size polycentricity perspective. Furthermore, the 20 urban agglomerations were classified into various categories with distinct morphological characteristics. The results are conducive not only to providing decision-making suggestions for diverse urban agglomerations, but also to further probing into the relationship between them and social issues within the realm of applied geography.