Recognition Of Spatial Scope Of Chang-Zhu-Tan Urban Agglomeration Based On Spatial Syntax And Accessibility

As a new unit of national economic development and social construction,urban agglomerations have produced many problems worthy of study during the development process.Among them,the identification of the spatial scope of urban agglomerations is the basis for studying the problems of urban agglomerations.From the perspective of development,the spatial scope of urban agglomerations refers to the spatial self-organization area that is driven by factors such as economic development and transportation links during the development and formation of an urban agglomeration,or it may be the area under the influence of the core city's radiation agglomeration capacity.Only by reasonably dividing the spatial scope of the urban agglomeration can it adapt to the new trend of economic development in the new era and promote the powerful integration of the resources of various sub-cities within the urban agglomeration.However,the current research on urban agglomerations in our country is still in its infancy,and a unified scope definition standard has not been formed,especially the lack of identification research based on the essential characteristics of urban agglomeration development.Many methods in current research ignore the spatial heterogeneity,resulting in the inability to show the development differences between different regions within the urban agglomeration.Therefore,in response to the above problems,this study uses spatial syntax,accessibility analysis methods and Densi-Graph methods to identify the spatial scope of the Changzhutan urban agglomeration on the basis of multi-source data.The main work content is as follows:1.First,use road data combined with space syntax to construct an axis diagram model for the Chang-Zhu-Tan urban agglomeration,and integrate the different indicators of the spatial syntax into the "urban agglomeration degree".According to the calculation results,the "city cluster degree curve" is fitted to the research curve,and the threshold is calculated to finally identify the spatial range of the urban agglomeration.2.On the basis of the cost distance algorithm,the terrain grid,surface coverage grid and traffic situation grid are added to the common road cost grid.The three comprehensively form a real cost grid,and the 30-minute isochronous circle is used as the scope to delimit the spatial scope of the urban agglomeration on the basis of the real cost grid.3.Finally,the Densi-Graph method is used to identify the spatial range of urban agglomerations using POI data,and the three methods are combined to obtain the final urban agglomeration spatial range.This scope explains the spatial scope of urban agglomerations from three aspects: spatial level,time accessibility,and regional service capabilities.On the basis of this scope,we take the 2015 data as an example to study the development of Changzhutan urban agglomeration.The area of this scope accounts for about 8.43% of the entire Changzhutan city,the GDP accounts for about 50.43%,and the population accounts for about 35.9%..The economic development in this area is good,the population density is high,and the industrial structure is dominated by high-precision and scientific research,information technology,and high-end service industries.It is a veritable core that can well lead,drive and radiate the development of surrounding areas and cities.