Application And Research Of Virtual City Microscopic Traffic Simulation System Based On VR/GIS Integration

Virtual Reality Geographic Information System (VR/GIS), as the key technology of the 'digital earth', is a new direction of the combination of Virtual Reality (VR) and Geographic Information System (GIS) technology. VR/GIS technology and its application in the virtual city microscopic traffic simulation are explored with the main pattern of comprehensive application of interdisciplinary in the dissertation. The main content is as following:1) The virtual city microscopic traffic simulation system, which is based on VR/GIS integration, needs to take the urban scene as its spatial foundation. For this point, the key technologies for massive terrain rendering under the condition of common computer hardware, the real-time rendering performance technology based on GPGPU, the problem of modeling and visualizing the 3D models are studied in this dissertation. On the basis of this, a virtual software environment has been developed for city microscopic traffic simulation by using the algorithm of texture rendering based on GPU while combining with the model simplification technology.2) The urban microscopic traffic simulation model has been developed based on traffic engineering theory, GIS and computer simulation technology which involves network model by GIS, microscopic traffic simulation model, analysis decision model, VR output model. The fast implementation of building traffic network and the automatic establishment of the topology relation can be easily realized. Establish the traffic simulation model, including vehicle generation model, signal control model, vehicle action model and route choice model. The analysis decision model provides a scientific basis for traffic project in terms of feasibility study, implementation effect and project optimization. A real-time interact 3D interface can be provided for user by VR output model. 3) On the basis of the road topologic structure, the correlation analysis of intersection and the road traffic flow characteristic analysis, a division approach of the traffic control work zone was presented in detail. In addition, taking one city road network as an example, proposed the actual traffic control area was zoned by using the model and algorithms; the result reveals algorithms are effective and feasible in the respect of the accuracy and efficiency of simulation.4) To provide more accurate and more effective short-term traffic flow prediction is the key technology for the intelligent transportation system due to the complexity and non-linear characteristics of city traffic flow. According to real-time acquisition data of link traffic flow, one kind of traffic flow prediction measure based on microcosmic simulation technology was put forward. The algorithm predicts the short-term traffic flow based on equal-dimension and new-information gray model. Finally, the prediction model was proved to have very good precision and practicability by example.5) The function and characteristic of city region oriented VR/GIS integration platform are introduced in this dissertation, while a virtual city microscopic traffic simulation system has been developed based on VRGIS platform. The general design objectives and basic principles of the system are described. The overall structure of virtual city microscopic traffic simulation system has been designed and completed; meanwhile, the function and technical realization of subsystems are analyzed.6) The feasibility, rationality and the application of VR/GIS technology in the field of virtual city microscopic were demonstrated by taking Newcastle as the research object. The current situation and comparison among the three planning schemes are simulated by using the system. The result of the research can be used as the foundation for decision-making for planning governor.