Data Model Of Public Transport Network For Modelling Space-time Accessibility

The space-time accessibility can dynamically reflect the difficulty of reachingdifferent location of public transport network, and provide immediate travelreferences to bus passengers. Compared with the traditional space accessibility,adding the time dimension brings more data and complicated relationship of thesedata, and puts forward higher requirement for data storage and management ofdatabase. As the core of database, data model can do spatio-temporal dataorganization more effectively to meet the data requirements of space-timeaccessibility and provide basic data support for it. Therefore, modeling reasonabledata model of public transport network has important significance to the research ofmodeling space-time accessibility of public transport network.Based on the analysis of the spatial accessibility model of public transportnetwork，this paper proposes a space-time accessibility model of public transportnetwork considering the lack of temporal constraints and the shortage of spatialconstraints for the existing model. According to the needs of the spatio-temporaldata and the spatio-temporal relation for the related algorithms in this space-timeaccessibility model, corresponding modeling principles and objectives of thespatio-temporal data model is determined.For the connectedness, directivity, timeliness and other public transportationnetwork characteristics, this paper analyses the spatial and temporal characteristicsof the public transportation network and builds the public transportation networkspatio-temporal data model for Space-Time Accessibility, using the object-orientedmodeling method and the unified modeling language.In the basis of modeling, the author builds the space-time accessibility-orientedpublic transportation network temporal geographic database making use of theGeodatabase, and completes the transformation from object-oriented model toGeodatabase data model through the unified modeling language, and aslo creats theassociated feature dataset, feature class and object class model elements to ensurethat the expression of spatio-temporal data and spatio-temporal relation is integral.According to the transformed Geodatabase model， the author builds thecorresponding public transportation network database in ArcCatalog10.0, andmoves the existing spatio-temporal data and the bus arrival time data of Harbin intothe database, then exchanges the data format and increases spatio-temporalconstraints. Combined with the proposed position-dependent analysis method ofspace-time accessibility of public transport network, tests of space-time accessibility expression in ArcGIS10.0have been made to prove that thespatio-temporal data model of public transportation network established in thispaper is effective.