Spatial Expansion of Urban Network for the Three Coastal Agglomerations of China: A study Based on Integrated Traffic Information Network
Sun Yang;Yao Shimou;Zhang Luocheng;Key Laboratory of Watershed Geography, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences;University of Chinese Academy of Sciences;
In the regional spatial organization established based on the logic of spatial flow, the development of intercity transportation and information network is changing the depth and extent of the social economic spatial structure. Therefore, time-space compression leads to the considerable consolidation of informational linkage among cities and further facilitates the constant expansion of the network space of modern cities under the effect of spatial flow. This study analyzes the spatial expansion of urban information for the three coastal agglomerations that emerged during the urbanization of China, namely, the Yangtze River Delta, Beijing-Tianjin-Hebei, and the Pearl River Delta Urban agglomerations. The findings are provided as follows: 1) Highway,ordinary train, high-speed train, and information network have transformed interconnecting cities to functional network nodes for the external expansion of urban information, shortened the temporal and spatial distance between the nodes and the surrounding cities, and driven the formation of a networking structure of information for urban agglomerations; 2) The spatial expansion of the urban information on the Yangtze River Delta Urban agglomerations is mainly composed of key node cities, including Shanghai and Nanjing. The networking degree of the northern area is higher than the linear connection degree of the southern area, and the regional linkage density declines sideward from the Shanghai-Nanjing and Shagnhai-Hangzhou lines; the spatial direction of urban network is Shanghai→Huzhou, Shanghai→Ningbo, Shanghai→Taizhou, Nanjing→Yangzhou, Nanjing→Zhenjiang, Nanjing→Wuxi, Nanjing→Suzhou, Nanjing→Shanghai, Hangzhou→Ningbo; 3) The urban information of the Beijing-Tianjin-Hebei Urban agglomeration mainly diverges from Beijing and Tianjin to form a network connection with secondary cities, including Langfang, Cangzhou, Chengde, and Zhangjiakou,the spatial direction of urban network is Beijing→Tianjin, Beijing→Shijiazhuang, Beijing→Qinhuangdao, Beijing→Langfang, Tianjin→Qinhuangdao, Tianjin→Shijiazhuang, among others. Beijing, Tianjin, and Shijiazhuang form the core circle layer of the degree centrality network, whereas the other 10 low-degree centrality urban nodes form the periphery low-density circle layer; 4) The urban information of the Pearl River Delta Urban agglomerations diverges from Guangzhou, Shenzhen, and Zhuhai to form a network connection with secondary cities, the spatial direction of urban network is Guangzhou→Shenzhen, Guangzhou→Zhaoqing, Guangzhou→Dongguan, Shenzhen→Guangzhou, Shenzhen→Dongguan, Zhuhai→Dongguan, including Foshan,Huizhou, and Jiangmen. Guangzhou and Shenzhen are located as the absolute center of the network. Guangzhou, Shenzhen, Dongguan, and Foshan form the core circle layer of the degree centrality network, and other 7 low-degree centrality urban nodes form the periphery low-density circle layer. The network features a recognizable‘core-periphery'structure.