City Network Of Urban Agglomerations In The Middle Reaches Of The Yangtze River In The Perspective Of Space Of Flows

The information and communication technology revolution represented by digitalization,the Internet,and mobile terminals has profoundly changed the way of social operation in the past.Information is instantaneously interacted through virtual networks.The material and people achieve rapid displacement relying on modern aviation,high-speed railway,intercity express transportation and other new modes of transportation.The original isolated cities are contacted by human flow,material flow,information flow,technology flow,capital flow,etc.and it promotes the birth of a new social space with characteristics and driving force which called the space of flows.Under the logic of the space of flows,various flows increase the degree of freedom of location,shorten the distance of traditional geographical connections,impact the traditional central place theory,and transform the urban system organization from urban level to urban network.Urban agglomerations are spaces that interact within a certain geographical area and are organically connected.With the advancement of global urbanization and informatization,the development of urban group and regional integration has become the trend and mainstream of global regional development.The middle reaches of the Yangtze River are located in the geographical center of China.It is one of the three major inter-regional urban agglomerations in the Yangtze River Economic Belt and is an important support for the rise of the Central Region.Studying the network structure of the urban agglomerations in the middle reaches of the Yangtze River and promoting its integrated development process have strategic significance for the development of China's urban system.From the perspective of the comprehensive analysis of virtual information flow and physical human flow,this paper uses the Baidu Index and Tencent migration data as the basis data,and uses the dominant flow analysis method to analyze the network structure characteristics of the urban clusters in the middle reaches of the Yangtze River from two dimensions: external network and internal network.The results show that:(1)The annual fluctuation of the virtual external network strength of the middle reaches of the Yangtze River is not obvious,but it shows obvious peaks before and after the Party' s Birthday,which shows the important position of the red culture of Hunan,Hubei and Jiangxi in the country.The strength of the external physical network changes greatly with time.During the holidays,especially the Spring Festival,the network strength rises sharply.The characteristics of population movement before and after the Spring Festival show that the urban agglomeration in the middle reaches of the Yangtze River is an important labor exporting place.(2)In the both of virtual external network and physical external network,the urban agglomerations in the middle reaches of the Yangtze River are closely related to the four major urban agglomerations which consists of Beijing-Tianjin-Hebei Urban Agglomeration,Yangtze River Delta Urban Agglomerations,Pearl River Delta Urban Agglomeration and Chengdu-Chongqing Urban Agglomeration,and form the “Ten” pattern.The status of Chengdu-Chongqing Urban Agglomeration in the virtual external network is stronger than in the physical external network,and the other three urban groups have a relatively balanced position in both of the virtual and physical networks.(3)Administrative divisions,geographical proximity and urban energy levels are three important influencing factors which affect the relationship between the central cities and other cities.(4)The virtual internal network density of the middle reaches of the Yangtze River is greater than the physical network density.The internal network density of the three subgroups is greater than the urban density of the entire middle reaches of the Yangtze River.(5)The virtual internal undirected network of the middle reaches of the Yangtze River is the Wuhan-Changsha dual-core structure,while the physical internal undirected network is the Wuhan single-core structure.The backbone network and the main network are regional core networks,which use less than 10% of the streamlines bear more than 50% of the flows.(6)There is no dominant city over global scope in both of the virtual and physical internal directed network.Wuhan,Changsha and Nanchang play a leading and controlling role only in the corresponding subgroups.It is worth mentioning that Pingxiang crosses the administrative barrier in the physical network.It's largest advantage flow does not flow to Nanchang,but flows to Changsha,becoming a secondary city dominated by Changsha,and opening the trend of inter-district integrated urban network.