Research On Dynamic Interaction Of Urban Space Based On Trajectory Data

Studying the urban spatial structure is the main form and way to explore the relationship and interaction between the various elements of the city,which is of positive significance to the layout planning and management of urban space.The travel trajectory of urban residents can truly reflect the operation of urban traffic and show the spatial interaction between different plots within the city.Therefore,the deep mining of urban mobile trajectory data is beneficial to the optimization of urban road network structure,and is helpful to understand the dynamic interaction characteristics of urban space.It is also of great significance to intelligent transportation and urban planning.Based on the GPS trajectory data of 3000 taxis in Lanzhou city and complex network theory,the topological characteristics of the urban road network and the dynamic evolution characteristics of urban spatial structure in Lanzhou city are studied.The main researches are summarized as follows:(1)The topological structure and the complexity of the urban road network in Lanzhou city are studied.Based on urban road network of Lanzhou city,the primal approach is used to build the complex network of road network,and the traffic flow on the road sections is used as the edge weights.The undirected weighted complex network is established.On the one hand,the betweenness of nodes and visual analysis are carried out to identify the key intersections of the road network.The results show that the distribution of the betweenness of nodes is not uniform,the main roads are dominated by east-west direction,and the direction characteristics cause the imbalance of the road load.On the other hand,the Louvain algorithm is used to identify the community of the complex network.The results show that the community structure of urban road network in Lanzhou city is more obvious and the quality of division is better.There are a great difference in the number of community and a marked change of community structure during the peak periods of the working days and rest days.(2)The dynamic evolution characteristics of urban spatial structure in Lanzhou city are studied.The urban areas are divided by grid method and the traffic volume between urban grids is analyzed.Given nodes that represent grids and link weights that define the frequency of interaction between them,the dynamic directed weighted complex network is established.The Infomap algorithm is used to identify the urban community of Lanzhou,and the modularity is used to demonstrate the effectiveness of our method.At the same time,the visualized analyses of urban community are presented and the spatio-temporal evolution characteristics of city structure are analyzed.The results show that there is a great difference in the spatial interaction of the rest and working days.The distance and scope of spatial interaction on the working days are larger than those of the rest days,and the spatial interaction is more close.The urban spatial interactions are also different between peak and off-peak.Urban spatial interaction changes dynamically over time.