Study On The Spatial Structure Evolution Of Huaihai Urban Agglomeration

This paper takes the Huaihai urban agglomeration as the research object.Starting from the relevant theories of urban agglomerations,the nine prefecture-level cities and the 42 counties under its jurisdiction are the research units,from the “carrier” and “skeleton” of the urban agglomeration.The three aspects of "morphology",that is,the combination of "point-line-surface",the 2007,2010,2013 and 2016 time profiles are used to explore the evolution characteristics of the spatial structure of the Huaihai urban agglomeration in the past ten years,using the centrality index.Method,entropy method and GIS spatial analysis method measure the urban centrality and urban comprehensive strength of Huaihai urban agglomeration;using the gravity model,membership model and breakpoint model to measure the economic flow,traffic flow and information flow of Huaihai urban agglomeration The strength,direction and its range of influence,and the three elements are reconstructed to reconstruct the existing spatial pattern of Huaihai urban agglomeration;social network analysis method is used to analyze the spatial network characteristics of Huaihai urban agglomeration;finally,Huaihai is summarized from different aspects.Problems arising in the evolution of urban agglomerations,and corresponding optimization strategies are proposed.The main conclusions are as follows:(1)From the perspective of “point”,Xuzhou's central index and comprehensive strength score lead the entire urban agglomeration and are the core cities of the Huaihai urban agglomeration.The rankings of cities in the urban agglomeration show the characteristics of “the two ends are relatively stable and the middle order is slightly changed”.The comprehensive strength of the region is mainly reflected in the three aspects of scale strength,economic growth strength and ecological health strength,“Lunan>Subei>Yudong>Wanbei.The spatial pattern of “points” is generally higher in the east than in the west and higher in the north than in the south.The hierarchical structure has evolved from “3+1+3+2”(2007-2013)to “1+2+4+2”(2013-2016),the spatial imbalance has intensified,and the“core-edge” structure has become increasingly prominent.(2)From the perspective of “line”,various elements are increasingly accelerating within the Huaihai urban agglomeration,and the links are increasingly close,and the adjacent groups are closely related.The economic linkage structure is transformed from a single-center linkage structure dominated by Xuzhou to a complex multi-center linkage structure;the traffic linkage structure gradually evolves from a simple "one"-shaped structure to a "?"-shaped spatial structure;At the same time,the spatial structure of information connection is more complicated,and the main contact skeleton gradually presents the form of “one axis + two triangles”.The total amount of various elements in Xuzhou is the highest in the region,so most cities regard Xuzhou as the primary connecting city.The contact direction of the element flow has obvious central cities,neighboring cities and traffic directivity.In some years,the characteristics of crossregional directivity also appear.Under the influence of the comprehensive factor flow,the Huaihai urban agglomeration was reconstructed into three major groups: the Xuzhou Group with Xuzhou as the center,the Linyi Group with Linyi as the center,and the Huaibei Group with Huaibei as the center..(3)From the perspective of “face”,the economic interactions of counties and cities in Huaihai urban agglomeration are becoming more frequent,the density of connected networks is increasing and the network structure tends to be stable.The “core edge” structure level is obvious,and the spatial distribution is dispersed from concentration to concentration.In addition to Shangqiu,the rest of the counties and cities gradually broke the administrative barriers,and the neighboring counties and cities were surrounded by each other.The Huaihai urban agglomerations basically formed four subgroups.The internal exchanges of each sub-group were close and the cooperation between sub-groups gradually matured.(4)According to the spatial analysis of the above three dimensions of “point-linesurface”,it can be concluded that there are mainly weak central cities,significant differences in linkage strength,low overall development level and market administrative barriers in the evolution of Huaihai urban agglomeration spatial structure.The main problems are proposed from the aspects of strengthening the strength of the central city,rationally locating the secondary central city,strengthening the internal and external links,improving the regional spatial structure,promoting the integration development and integrating into the national regional development strategy.