Discrimination Of Urban Center Structure And Analysis Of Influencing Factors Of Commuting Efficiency

With the acceleration of urbanization,the scale of cities is expanding day by day.The negative external effects of population agglomeration in single center cities make urban traffic problems increasingly serious.Urban managers try to guide the transformation of transportation mode from the perspective of urban spatial planning,adjust the relationship between supply and demand,and alleviate traffic problems.Central structure identification is an important step in urban spatial planning,but it is still limited in analysis methods and data application.In addition,in order to develop more effective measures to optimize the commuting efficiency,it is necessary to analyze the influencing factors of commuting efficiency in cities with different central structures.In this context,this paper uses the commuting data from Baidu location data mining to identify the central layout of 35 major cities in China based on grid density clustering,and discriminates the urban central structure according to five commuting mode indicators.Finally,it analyzes the factors that affect the commuting efficiency under each central structure.(1)Urban center layout recognition based on grid density clustering.Through data preprocessing,we get the commuter data based on Baidu location information.Based on the grid model and center energy level measurement index,an improved DBSCAN(density based spatial clustering of applications with noise)density clustering method is established.Combined with the planning and design of the primary and secondary centers of each city,the identification of the layout of 35 city centers is realized,and the identification results are visualized.(2)Based on the five commuting modes,the urban center structure is distinguished.This paper establishes five hypothetical models of commuting modes: maximum disorder mode,single center mode,balanced multi center mode,constrained diffusion mode and unbalanced multi center mode,and puts forward the quantitative indicators of commuting distance distribution and job residence allocation under each commuting mode to distinguish the central structure of 35 cities.The results show that most cities in China are unbalanced multi center structure,which shows that the development of sub center is immature and the independence of sub center is low;The second is the single center structure with Lhasa as a typical case,and the main center employment accounts for more than 60%;And a few of them show the balanced polycentric structure of Shenzhen;The largest disordered structure can not describe the central structure of 35 cities.The results can provide some reference for urban planners to carry out macro layout.(3)Analysis of factors influencing commuting efficiency in different urban central structures.From the three dimensions of social economy,spatial structure and transportation facilities,this paper selects the influencing factors of commuting time consumption and makes a correlation analysis.In each center structure,we do multiple regression on the related variables of commuting time consumption.After controlling the influence of other variables,we can more accurately verify the influence relationship of each factor on urban commuting time consumption.The results show that for any kind of city structure,city size is one of the most important factors affecting commuting efficiency.Under the unbalanced multi center structure and single center structure,keeping the balance between work and residence is also an important means to improve the efficiency of commuting.In the urban spatial planning,we should choose the appropriate development mode of central structure according to the economic conditions,urban scale and infrastructure construction level of the city itself.This paper studies the urban central structure of 35 major cities in China by using massive commuter data.From the perspective of coupling development of spatial structure and traffic organization,it puts forward the optimization strategies of urban commuter efficiency under different central structures,which has certain theoretical value and practical significance for the healthy development of spatial structure and traffic system of big cities in China..