Study And Application Of Optimization Method Based On GIS-T For Urban Public Transport Network

At present,the Transportation Geography Information System (GIS-T) technology is maturing gradually.TransCAD software,which combines GIS with the transit model functions,is designed to help transportation specialists and related organizations save,show,manage and analyse transportation information and data.Its functions are powerful in space analysis,and it will be more reasonable and effective by using this software to assist urban public transport network optimization.According to the urban public transport network characteristics and existing transitplanning models,TransCAD database,model mechanism and operation process are studied,transit network evaluation indexes and optimization technology based on the TransCAD are explored,and TransCAD has been better applied in the main skeleton of conventional public transportation network optimization operation service stage.All of above are considered.Based on TransCAD,the following research contents are involved in the public transport network optimization application analysis:(1) Primary characters of the urban transit network are analyzed,the transitnetwork database based on TransCAD are discussed,the method and process of establishing database are provided,the methods of TransCAD display and data edition are introduced,a Transit Route System is established by using Route System toolbox,a basic transit OD matrix is set up on the investigation of inhabitant trip in 2006 in Urumqi city .(2) The model principle of four steps in passenger flow forecasting is illustrated and the software flowchart combining the TransCAD technology with the transit planning model is listed,gravity model is calibrated,and passenger flow assignment on the layer of transit network is realized.(3) urumqi scheme as a supporting project is presented: the method to obtain the network optimization adjustment of the urban main skeleton of conventional public transportation network is discussed by using TransCAD on the base of the forecasted passenger flow result.(4) The transit network evaluation indexes are necessary in the urban transit planning.According toeach characteristic of all network indexes,the indexes computation is illustrated by using the powerful space analysis tool of TransCAD.(5) the paper evaluates and testes the scheme of urumqi urban transit network optimized.