| In the context of high-quality development in the new era,the urban agglomerations’ strategy is shifting to regional coordinated development,new urbanization and dual circulation.This process is not only a process in which the central cities drive the surrounding small and medium-sized towns and cities to the coordinated development,but also a process in which cities of different scales are optimized for spatial connections,and a process in which the expansion of domestic demand and formation of dual circulation are promoted.The economic links and space allocations of central cities,towns and cities of different scales have also become the main trends in the study of urban agglomerations.Central Jilin Urban System has its own development characteristics due to the external environment and internal development mechanism.It is of great significance to propose a scientific analysis of its economic connections and spatial patterns,which will enable it to exert its comparative advantages,improve the efficiency of factor allocation,and commit to high-quality development.Central Jilin Urban System is an important strategic support for HarbinChangchun Urban Agglomeration and an important link connecting the Central and Southern Liaoning Urban Agglomeration.Central Jilin Urban System is also an important area for the construction of China-Mongolia-Russia Economic Corridor and Changchun-Jilin-Tumen development and opening pilot zone.Its linkage development will have a huge impact on the optimization of Northeast region’s spatial pattern and Northeast revitalization.Therefore,this study analyzes the evolution of Central Jilin Urban System’s economic connections and spatial patterns from 2004 to 2018,with a view to promoting the overall development of urban agglomeration and regional integration.(1)Theoretical analysis and literature review.The paper analyzes the concepts of urban agglomerations,economic connections,spatial patterns and network structures.It sorts out the regional connection theories of regional interdependence,interaction,agglomeration and diffusion;spatial structure theories of growth poles,point-axis systems,network development,and center-peripheral.It summarizes the domestic and foreign research progress of economic connections,the spatial patterns of urban agglomerations,and Central Jilin Urban System that are related to the research theme.(2)Analysis of the development status of Central Jilin Urban System.The paper determines the scope of research area,and understands the development status.It summarizes the development background and natural environment conditions of Central Jilin Urban System.Based on the statistical index data of GDP,population and industry,a descriptive statistical analysis of city size and economic development in Central Jilin Urban System is carried out.(3)Analysis on the evolution of economic connections in Central Jilin Urban System.The paper constructs a gravitational index system from two aspects of comprehensive economic development level and accessibility,and obtains data on the relationship evolution of economic connections of cities and counties.The level of comprehensive economic development includes four aspects: economic development strength;investment and consumption level;people’s living standards;infrastructure,technology and education.Accessibility takes into account the time distance of road and rail,opportunity cost of population mobility.According to the results of evolution data,it analyzes the evolution characteristics of comprehensive economic development level,intensity and direction from 2004 to 2018.The analysis finds that the urban agglomeration is at the stage of "point-axis",and has a transition tendency to "hub-andspokes".The core city’s influence trend is prominent.The influence area of Changchun is basically within the space of metropolitan area.A cross-shaped development axis has been formed and consolidated.The southern gateway axis and Shulan-Meihekou development axis are still in their infancy.At the same time,based on the data of latest parent and subsidiary companies and enterprises supply chains that characterize industrial connections,it analyzes the content of economic connections,highlighting the role of core city,development axes,and key cities.(4)Analysis on the evolution of spatial patterns in Central Jilin Urban System.Relying on the relational data obtained from the gravity model,the evolution of spatial patterns is analyzed from the spatial characteristics of connection nodes,clusters and overall spatial pattern.Using the point degree centrality and dominant level to analyze the changes of associated nodes,the analysis finds that the hierarchical status of each city and county has been in a relatively stable state for 15 years,and the changes in the value of each connection level have experienced an equilibrium-disequilibrium spiral upward process.It uses Fast Unfolding algorithm to identify the closely-connected town clusters at different stages,and the number of cluster identifications is changed from 5 to 3.Using regional polycentric algorithm to analyze the changes in the overall spatial morphology,it is concluded that the urban agglomeration is dominated by polarization development,and the overall network level is low.The urban agglomeration also presents the development trend of concentration-diffusion effect centered on the Changchun urban area,the axes connection between Harbin-Dalian axis and Changchun-Jilin-Hunchun channel,and point-to-point cross-city connections.(5)Countermeasures and suggestions for economic connections and spatial optimization in Central Jilin Urban System.According to the analysis results of evolution,the relevant countermeasures and suggestions for the optimization of economic connections and spatial patterns are discussed from the aspects of infrastructure interconnection,industrial layout and upgrading,deepening of connections,expansions of central cities and core areas,and optimization of spatial structure layout. |
