Spatial Structure Of Urban Functions Of Changchun In The Perspective Of Polycentricity

Polycentric strategy derives from the urban planning study for the garden city and satellite cities,new city and organic evacuation theory.The original purpose is to solve the problem of big city center congestion,traffic and environmental problems.As an economical way of urban spatial organization,Polycentric strategy has got the extensive attention of scholars in recent years.Some existing studies have shown that polycentric structure has higher economic performance,and can effectively reduce the use of urban commuting time.In fact,polycentric structure has grown up to be a common trend in big cities in the present.“Polycentricity” has become a lingering complexity of the urban spatial structure in planning in big cities,especially the mega cities,in China.Urban functional space is the urban geography and urban planning focus of research.In recent years,with the rapid development of economy and the rapid expansion of urban space in China,the development way of giving priority to incremental planning is becoming increasingly unattainable.Unorderly spreading of big cities has not only corroded a lot of land resources but also caused a series of social questions.As cities spread of disorder,residents live a separation,the city function is misplaced,low efficiency of land use,infrastructure problems such as imperfect,severely hampered the sustainable development of the city.The rapid advance of information technology,also has brought the city living,production,consumption,entertainment and so on various aspects of enormous change,make urban functional spaces show flat,compound,complex diversified development trend.In recent years,with wide use of geographical big data,it has become a new trend to study the spatial structure of urban function space with a quantitative method.Based on the POI(point of interest)data in the center district of Changchun,the study focus on five types of functional space: living space,office space,commercial space,leisure space and traffic space.Based on the demand of theory and practise of subjects development and the policy innovation,in the perspective of polycentricity,this paper focus on the spatial structure of urban functions of Changchun from spatial pattern of function,functional space center link,functional elements of multi-scale composite and functional mechanism of spatial organization pattern.Major contents of this article are as follows:Part Ⅰ(Chapter 1 and chapter 2): Chapter 1 is the introduction part.First of all,on the basis of the paper’s research background,which leads to the scientific problems of thesis;the paper has been clear about the research goal,significance and the research idea,and then introduced the general situation of the development of the study area;Finally,the paperstudies data acquisition and processing,the research methods used are described in detail.Chapter 2 is the theoretical discussion on urban functional space.In the definition of urban function,on the basis of spatial correlation basic concept,Focusing on the formation mechanism of urban functions,urban functions evolution,functional space layout,functional space reconstruction,functional space organization mode and functional space matching,the paper combed the related content of urban function space research at home and abroad.This part also introduced the main point and basic content of polycentric theory,functional division theory and the Mixed-use theory.Part Ⅱ(Chapter 3,chapter 4 and chapter 5): Chapter 3 is the development and spatial distribution of urban functional space.Based on the POI data,the study focus on five types of urban function: living,office,commerce,leisure and transportation.On the basis of the connotation of each function space is introduced.The evolution and distribution pattern of functional elements of each function space is thoroughly analyzed.Then,further discusses on the characteristics of agglomeration and dispersion of different formats within each functional space.The results show that the spatial distribution of different functional elements in Changchun entails coexistence of concentration in the core area and diffusion in the peripheral area.Chapter 4 is the analysis of commuting connection of different functional space center.Firstly,on the basis of the analysis of identification and definition methods of urban functional centers at home and abroad,this paper proposes a method based on kernel density estimation and local autocorrelation to identify the urban function center.Secondly,through the identification of the functional centers of each functional space,the distribution range of each functional center is defined and the energy level structure of each functional center system is analyzed.Then,based on the connotation of functional multicenter,the method of parameter substitution is used to analyze the multicenter correlation features of each functional space.Finally,from the perspective of urban commuting,taking the residential space as the basic space.This paper analyzes the characteristics of commuting associated with the other three functional spaces.The results show that the morphological characteristic of multicenter is significant;functional mismatching phenomenon is obvious.Chapter 5 is the analysis of mix-use development of urban functional space.Based on introducing the connotation of city function,discusses the city functions compound in different spatial scales.Functional complex features of Changchun are measured by location entropy analysis and entropy index based on the grid.Finally,from the two dimensions of the urban area and urban block,this paper makes an in-depth analysis of the functional location of the functional elements and the characteristics of the functional compound types,and discusses the compatibility between different urban functions.The results show that the spatial heterogeneity of the degrees of mixed use is significantly.The primary determinants ofthe spatial distribution of mixed use were the distribution of land price and the quantity of leisure elements.Part Ⅲ(Chapter 6 and chapter 7): In Chapter 6,the structure and optimization of urban functional space are discussed.Based on the superposition of multi function center,this paper summarizes the multicenter structure model of urban functional space in Changchun from two aspects,namely,multicenter and multi function.Then,the impact of macro-control,from the historical factors of city development of public policy and the scale effect of agglomeration economy driven,consumption structure and behavior,the functional elements of the intrinsic characteristics of choice,innovation and technology progress of traffic and other aspects,this paper analyzes the forming mechanism of urban function space structure,and discusses the optimization strategy of functional space structure.The 7 chapter: Conclusion and prospect.The main conclusions of the paper are presented based on the summary of each chapter.This part also analyzes the characteristics and innovations of the research,and points out the shortcomings and prospects of the research.