Research On The Spatial Structure Of Urban Agglomerations In The Yangtze River Delta Based On The Land Transportation Network And The Passenger Flow Of Highways And Railways

The land transportation network and the passenger railroad flow represent the traffic physics network and the organization network respectively.which embody the two major traffic geography concepts of accessibility and mobility.At present.there are abundant research results on the traffic accessibility and mobility,but there are few of comparative and combined research.To explore the comprehensive utilization of road network data and "stream space" data is a useful attempt to jointly study the accessibility and mobility of traffic geography.With Anhui,North of Jiangsu and other regions being classified as a part of Yangtze River Delta Urban Agglomerate,the scale of Yangtze River Delta Urban Agglomerate has expanded,the grades of large,medium and small cities are complete,and the process of regional integration has been accelerated.The research of current status on the urban agglomeration spatial structure is conducive to grasping the advantages and disadvantages of the development of Yangtze River Delta Urban Agglomerate.Under the influence of different transport networks,the characteristics and status quo of the spatial structure of Yangtze River Delta Urban Agglomerate can be more fully and objectively reflected,providing a theoretical reference for the construction of world-class urban agglomerations.This article takes the 66 cities of the Yangtze River Delta City as defined in the"Yangutze River Delta Urban Agglonmeration Development Plan" issued by the State Council in June 2016 as the research object.The relevant literature on urban agglomeration structure research was combed,and the theoretical foundation and spatial interaction theory were used as the theoretical basis of this paper.The spatial analysis methods such as social network analysis.big data capture,GIS spatial analysis and cartographic expression are used to analyze the accessibility patterns,urban contact network hierarchy,and urban hinterland systems of Yangtze River Delta Urban Agglomerate.The results show that under the influence of the land transport network,the Yangtze River Delta urban agglomeration has an outstanding traffic channel proliferation phenomenon,and the accessibility along the Shanghai-Nanjing,Shanghai-Hangzhou,and Nanjing-Hangzhou lines is the best.while the daily exchange circle range is closely related to the urban geometric location.The central cities of the Yangtze River Delta are Shanghai,Nanjing,Suzhou,Wuxi,and Hangzhou.The polarization of the intensity of the link between cities is prominent.The density of high-level network layers decreases from east to west,and the high-level cities at the network level point clearly.The central cities of the Yangtze River Delta are Shanghai,Nanjing,Suzhou,Wuxi,and Hangzhou.The polarization of the intensity of the link between cities is prominent,the density of high-level network layers decreases from east to west,and the high-grade cities have higher contact rates.The city's hinterland is nested and the spatial attenuation law is significant.Under the influence of the passenger railroad flow,the accessibility of the urban agglomerations in the Yangtze River Delta presents a smooth and continuous expansion,and the regularity decay from around Taihu Lake.The geometric center-edge structure and the scale center-edge structure coexist,and the characteristics of the city's heightened urban counterparts in all level cities are prominent.Both the urban space links of highways and railways have the characteristics of high contact,and the two are very complementary,which highway links fill the vacuum of the railway connection to a great extent.spatial proximity and urban strength pointing features of city hinterland system coexist.There is a strong correlation between regional urban density and degree of development and urban grades and hinterland ranges.Based on this,compare the spatial structure of urban agglomerations based on land transportation networks and passenger railroad flows,and the results show that the two types of data jointly strengthen the central periphery of the Yangtze River Delta urban agglomeration centered on the Huning-Huhang-Ninghang Line.The passenger railroad flows data is more widely used in time measurement and different spatial scales,while the land transportation network data has more advantages in evolutionary research and spatial expression.Comprehensively utilizing the advantages and complementarities of the two,it puts forward opinions such as the improvement of the transportation network,the construction of new traffic nodes cities,and the planning of the metropolitan area for the current Yangtze River Delta urban agglomeration traffic network construction and urban layout.