Abstract:

The multi-level perspective and multi-scalar city network have gradually become the critical pathways to understand spatial interactions and linkages. The road linkages represent distinguished characteristics of spatial dependence and distance decay, which is of great significance in depicting spatial relationships at regional scale. Based on the data of highway passenger flows between prefecture-level administrative units, this paper tries to identify the functional structures and regional impacts of China's city network, and further explores the spatial organization patterns of the existing functional regions, aiming to deepen the understanding of city network structure and provide new cognitive perspectives for the extant research. The empirical results are shown as follows: (1) It is immediately visible that the highway flows are extremely concentrated on the mega-regions of eastern coastal China and major economic zones in central and western China. And city networks based on highway flows demonstrate strong spatial dependence and hierarchical characteristics, which to a large extent has spatial coupling with the distributions of major mega-regions in China. It is a reflection of spatial relationships at regional scale and core-periphery structure. (2) A total of 19 communities that belong to important spatial configurations are identified through community detection algorithm, and we believe that they are urban economic regions within urban China. Their spatial metaphors can be concluded in three aspects. Firstly, many communities have the same boundaries with provincial level administrative units, which reveals that significant administrative region economy still exists in contemporary China. Secondly, trans-provincial linkages can be formed through spatial spillover effects of mega-regions within specific communities. Thirdly, cities located in the marginal areas of provinces and attracted by powerful center cities in neighboring provinces may become increasingly disconnected with their own provinces and be enrolled into communities of neighboring provinces, which make contribution to the formation of the trans-provincial core-periphery structures. (3) Each community, with its distinguished city network system, demonstrates strong spatial dependence and various spatial organization patterns. Regional patterns have emerged with the features of a multi-level, dynamic and networked system. (4) From the morphology perspective, the spatial pattern of regional city networks can be basically divided into monocentric structure, dual-nuclei structure, polycentric structure and low-level equilibration structure, with the monocentric structure as the major type.

Key words: city network, urban economic region, urban system, regional division, monocentric structure, polycentric structure, community detection, China