Research On Spatial Characteristics,Connect Network And Optimize Allocationof Bus Stations In Downtown Area Of Lanzhou City

With the acceleration of urbanization,cities have been endowed with unprecedented economic,political and technological rights,and cities have inevitably been pushed to the center of the world stage,playing a leading role.At the same time,cities are facing challenges such as environmental pollution,traffic congestion,inadequate housing,employment,disease and so on.In this context,“smart city” has become a feasible road to solve urban problems,and it is also the trend of future urban development.Green transportation is an important part of modern smart city: on the one hand,the public transport system provides the most extensive and lowest cost arrival services in all functional areas of the city;on the other hand,as an intensive mode of travel,public transport can effectively alleviate urban road traffic congestion,improve traffic efficiency and reduce carbon emissions.Based on the POI data of the bus station in the downtown area of Lanzhou,this paper uses ArcGIS and Ucinet software to research the spatial distribution of the bus station in the downtown area of Lanzhou from two aspects of spatial characteristics and connected networksand provide suggestions for its optimization through the LocationAllocation model,in order to provide reference for the government to formulate relevant policies and optimize allocation of the stations.The following main conclusions are drawn:(1)From the perspective of spatial characteristics,research on the spatial clustering,functional format and accessibility of bus stations in downtown Lanzhou.Through the comparison of nuclear density analysis and DBSCAN spatial clustering,it is found that the cluster point of the bus station in the central city presents the spatial structure of “one main center and two sub-centers”.Secondly,statistics are made on all kinds of facilities within the radiation range of bus stations to distinguish their functions from residential function,commercial function,public service function and mixed function.It is found thatthe overall function distribution of the bus stations in the central city of Lanzhou is relatively average.The four functions are intersected in the routes,and most of them are distributed in the mixed land,so as to maximize the benefit of the station distributionand form several groups in some areas,thus ensuring the functional needs of some parts of the central city.Finally,through the density of the road network in the comprehensive buffer zone of the bus station,it is found that the overall accessibility of the bus station in the central city of Lanzhou is at a low level,and the high-level accessibility is scattered in Qilihe District and Chengguan District.(2)Analysis on the centrality of the connection network of the bus station in the downtown area of Lanzhou city.It is found that the Degree Centralityare greater than theBetweenness Centrality of the majority of the 694 bus stations in the downtown area of Lanzhou,and their average values are 370.61 and 132.40,respectively.It shows that most of the bus stations in the downtown area of Lanzhou have good direct access capability,but the connection with the other stations is poor,which is also related to the terrain limitation of Lanzhou CityThe typical valley-type zonal distribution characteristics of "two mountains and one river" make the city distributionin the narrow valley terraces.The terrain characteristics also determine the basic outline of the spatial distribution of bus stations lines.(3)The model of minimizing the number of facilities and minimizing the impedance in the location allocation model of ArcGIS software is used to provide a scheme for optimize allocation of bus stations in the central city of Lanzhou.Comparing the calculation results of two models: minimum facility number model and minimum impedance model,when the number of facilities is 708,the coverage rate of residential quarters and the sum of the distance from the request point to the facilities point are the best,taking into account the actual travel of residents and government construction.Therefore,a total of 708 bus stations in the downtown area of Lanzhou were selected as the most suitable optimize allocation plan.