PROGRESS IN GEOGRAPHY ›› 2022, Vol. 41 ›› Issue (11): 2018-2029.doi: 10.18306/dlkxjz.2022.11.003

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Evolution characteristics of compactness in the Yangtze River Delta from the perspective of coupled network

HAN Gang1(), TANG Le1,2,*(), LIU Zhimin3, ZHANG Guoqing4   

  1. 1. Faculty of Architecture and Civil Engineering, Huaiyin Institute of Technology, Huai'an 223001, Jiangsu, China
    2. Nanjing Institute of Geography and Limnology, CAS, Nanjing 210008, China
    3. Institute of Urban and Demographic Studies, Shanghai Academy of Social Sciences, Shanghai 200020, China
    4. Urban and Rural Planning Design Institute of Fuyang, Fuyang 236000, Anhui, China
  • Received:2022-03-28 Revised:2022-07-21 Online:2022-11-28 Published:2023-01-28
  • Contact: TANG Le E-mail:hregion@163.com;tangle910365@sina.com
  • Supported by:
    Social Science Foundation of Jiangsu Province(18EYC003);Project of Philosophy and Social Science of Jiangsu University(2022SJYB1947)

Abstract:

Regional compactness refers to the urban form of synergistic integration through effective interactions. In essence, it is the reallocation process of factors of production, affected comprehensively by many factors, such as spatial-temporal distance, economic scale, market competition, and policy cooperation. The Yangtze River Delta, one of the regions with the highest level of urbanization in China, has produced many practical problems that affected the coordinated development of the region towards the goal of integration and high quality development. Regional compactness is an expansion of the compact city concept in a larger space, which is considered a better geospatial model to achieve regional integration. Therefore, analyzing the evolution characteristics of compactness of the Yangtze River Delta is helpful for identifying the real stage of the Yangtze River Delta's integrated development and the key pathways of regional compactness construction and governance. This study evaluated the relationship of cities by variables of spatial-temporal distance. In the Yangtze River Delta region, intercity traffic characterizes multi-modal transportation, forming a coupled nested network composed of high-speed railways and highways. This study evaluated city compactness by the shortest travel time and travel path provided by the coupled network and constructed a compact network map. Furthermore, from the macro to the micro scales, it analyzed the spatial distribution and evolution of compactness characteristics from four aspects: The global spatial distribution, structure, the local node organization and location. The study found that the urban compactness of the Yangtze River Delta has obvious global differentiation characteristics. As time goes on, its uneven compactness distribution gradually became obvious, and its spatial agglomeration tends to be significant. At the local scale, city compactness is in the transitional period from agglomeration to equilibrium, and it tends to have the local high-clustering features at low cost in a stable state. With regard to the cities themselves, the role categories emerging from the local structure show a diversified selection mechanism.

Key words: coupled network, compactness, network motifs, Yangtze River Delta