中国城市群高铁通达格局与空间交叠特征

A well-developed transportation network can profoundly influence the spatial connection of cities and reshape the regional spatial pattern. This paper used 2021 high-speed railway passenger time data, and took the construction of "National 123 Travel Traffic Circle" proposed in the "Outline for the Construction of a Strong Transportation Country" as the starting point. It compares and analyzes the access patterns and differences of national urban agglomerations and central cities, and further uses the SLPA model to identify the community division and overlapping space of all high-speed railway connected cities in China, and explores regional development trend and the geographic characteristics of overlapping space. Some conclusions can be drawn as follows: (1) There were 15 urban agglomerations with 2-hour access to Chinese urban agglomerations, accounting for 79% of the total number of urban agglomerations, and the weighted average access time of cities showed a "circle-type" spatial pattern of expanding from the central area to the peripheral areas from low to high. (2) Most of the 3-hour access contour coverage areas of central cities are beyond urban agglomerations, showing the spatial characteristics of "cross-urban agglomerations". (3) The overlapping community discovery algorithm divides China's urban space into 14 communities, and there are only 3 communities west of the Hu Line. (4) The overlapping space was identified for the divided communities, in which 9 communities overlapping a total of 27 cities were generated. (5) In terms of spatial morphology, the overlapping cities were distributed in a point or belt pattern; in terms of spatial location, the overlapping cities are mostly located around the regional central city, and in terms of administrative divisions, they were mostly in the inter-provincial junction zone; in terms of urban function, the overlapping cities rely on the high-speed railway circulation channel, and through the transition and conversion function, they were manifested as a network connection bridge between communities. From the perspective of high-speed railway transportation, the regional spatial pattern showed cross-urban agglomeration linkage and group development, and the networked, interactive, and cross-scale role of overlapping spaces was highlighted. For the better development of the city and the region, for the characteristics of overlapping communities and overlapping spaces, communities can try to fill in the gaps and improve the inter-community capacity, while overlapping spaces can try to combine their own advantages to create more cross-regional connection possibilities.

Keywords： urban agglomeration; high-speed railway access patterns; overlapping community models; community division; overlapping spaces