Research On Urban Centricity Of Yangtze River's Midstream Urban Agglomeration

Urban centricity reflects the relative importance of a city serving other cities and regions.Based on the statistical data and statistical yearbook of Yangtze River's midstream urban agglomeration,this paper uses the entropy method and ArcGis spatial analysis method to analyze the urban center of the urban agglomeration in the period from 2005 to 2014,from the whole,regional and urban agglomeration a comprehensive evaluation of its center.The results show that:(1)In the city scale,the evaluation of the status of the city center,from the time point of view,Wuhan,Changsha and Nanchang city center position higher.Xiaogan,Xiangtan and Jingmen City center to enhance the status of the most obvious,Jingzhou City,the status of the city fell faster.From the spatial changes,Wuhan with excellent geographical advantages,strong economic strength and huge scientific and technological resources,making it the first city of the Yangtze River's midstream urban agglomeration.The function of the city's basic functions,from the time point of view,around the city's production functions,business functions,information functions,traffic functions,financial functions,science and education functions,cultural functions,medical functions have improved.Production functions,business functions and traffic functions improved significantly,while cultural,medical and financial functions to enhance the slower.From the point of view of spatial change,the functions of Wuhan,Changsha and Nanchang are prominent and fast,and the functions of the city are relatively complete.They are comprehensive cities and the rest of the cities are compared with each other.Evaluation of the city grade system,Wuhan and Changsha city belong to a central center,Nanchang and other 13 cities for the two central cities,Xiantao and other 16 cities are three central cities.(2)In the regional scale,the city center evaluation was carried out from three regions:Wuhan city circle,Chang-Zhu-Tan urban agglomeration and Poyang urban agglomeration.From the point of view of temporal evolution,the urban centrality of Wuhan city circle is the biggest difference,the average center and the central difference are increasing slowly.The average center of the Chang-Zhu-Tan urban agglomeration is high,the average center and the central difference are showing a slow upward trend.The city of Poyang urban agglomeration center of the lowest average,showing a slow upward trend,but the central difference is small and the trend is gradually narrowing.From the spatial distribution,Wuhan city circle,Chang-Zhu-Tan urban agglomeration and Poyang urban agglomeration show a "core-edge" structure.Among them,there is a polarization of the urban center of Wuhan city circle,and the urban center of Chang-Zhu-Tan urban agglomeration is more balanced than Wuhan city circle,the center of the eastern city is much higher than the western city.The urban center of Poyang Lake urban agglomeration is more balanced than that of the Wuhan city circle and Chang-Zhu-Tan urban agglomeration,smooth transition.(3)In the urban agglomeration scale,the central assessment of Yangtze River's midstream urban agglomeration shows an increasing trend in the temporal evolution.In the spatial evolution,the spatial distribution of the central space has the characteristics of discretization,the central city is in the "island" state,and the spatial development pattern of Wuhan and Nanchang "dual-core" is presented to Wuhan,Changsha and Nanchang "The development model changes,the urban system gradually improved but poor coordination between cities,radiation and diffusion is very weak.