Spatial Structure Analysis And Optimization Of Land Transportation Network In Guanzhong Plain Urban Agglomeration

The Guanzhong plain urban agglomeration has a unique strategic position in the national modernization and all-round opening pattern,and compared with other mature urban agglomerations,the Guanzhong plain urban agglomeration is still in the gestation stage and has a high degree of plasticity.The land transportation network is an important way to reflect the development pattern of urban linkages and urban agglomerations,and shapes the spatial development pattern of urban agglomerations.The structure of land transportation network in Guanzhong plain urban agglomeration not only affects the coordinated development of transportation network and region,but also influences the integration process of urban agglomeration.Based on this background,this thesis researches the spatial structure of land transportation network and its optimization in the Guanzhong plain urban agglomeration.This thesis firstly constructed a comprehensive evaluation index system for urban development quality of Guanzhong plain urban agglomeration,and evaluated the urban development quality by entropy value method.Spatial correlation model,locational degree model and social network analysis method were used to analyze the spatial structure characteristics of Guanzhong plain urban agglomeration under land transportation.Secondly,the topological structure of the land transportation network was quantitatively evaluated by selecting two syntactic variables,integration degree and penetration degree,in the spatial syntax,and its spatial correlation and spatial agglomeration were analyzed by using spatial autocorrelation.Finally,the optimization model of the land transportation network of the Guanzhong plain urban cluster was constructed with the optimization objective of maximizing the traffic accessibility of the global nodes of the network and the constraints of the construction cost and the length of the new single line.The optimization results were solved by MATLAB software algorithm,and the optimization plan of the land transportation network was further developed.The main findings of this thesis were as followed:(1)Both the quality of urban development and the urban linkage network under the land transportation network have a single core(Xi’an)pattern.The balance and network density of the urban linkage network under the road transportation network are better than those under the rail transportation network.(2)The integration and choice of land transportation networks at different scales have significant differences and evolve differently,but their high value areas match with the key development axes of urban agglomerations.The integration and choice of land transportation networks at different scales have positive spatial correlation,and the road transportation network is stronger than the rail transportation network,and the regional agglomeration is significant.(3)The global nodal traffic accessibility of the optimized land transportation network has been improved.The global node traffic accessibility of the road transportation network and the rail transportation network has increased by 0.0016 and 0.0018 respectively,with an increase of13.98% and 12.05% respectively.The optimization plan of the land transportation network of the Guanzhong plain urban agglomeration was also formulated in three aspects: upgrading the status of regional node hubs,building new key major transportation corridors and strengthening the connection between weak nodes.