Establishment And Application Of Macro-Simulation Model Based On GIS

With the fact that China accelerates the urbanization process, a large amount of population floods into cities, leading to traffic jam and frequently causing traffic problems. How to carry on an effective traffic simulation in accordance with the large city's traffic condition, and then help to make a reasonable traffic plan, have become an issue all large cities must face for a long term. Hence establishing a practical macro traffic simulation model and applying it to the design and implement of the traffic simulation system have a very big realistic significance.Now internationally, traffic simulation technology research has gradually become mature, more and more commercialized and professional traffic simulation software has been developed and devoted to the practical usage. However, China began to pay attention to traffic simulation since 80^th, 20 century, so China still falls behind other developed countries in the related technology field and the commercialized degree and covering degree of the software in China are over insufficient. Under such condition, it is relatively capable to directly use the high-level commercialized traffic simulation software from outside to resolve China's traffic problems. However, in practice there has a problem: whether the model adopted in the software suits China's traffic condition? In addition, most simulation software has the shortcomings including data closure and indirect result display.Firstly, based on the analysis and research of the macro-simulation model establishment theory and China's current traffic condition, this paper applies the relative technology to design and implement a macro-simulation model which accords with the big cities' traffic condition in China. This model is established following the four-step method: travel generation sub-model adopts the cross division algorithm, travel distribution sub-model adopts the gravity algorithm, travel type division sub-model adopts the contribution rate curve algorithm, and flow assignment sub-model adopts the algorithm based on the shortest path method and increment assignment method. Secondly, by applying the above model and combining with GIS, a macro-simulation system is designed and developed, which can directly reflect and display the future traffic condition. At the same time, the system unifies the data management to the rational database management system in order to resolve the data closure problem of the current simulation software. This improvement will provide the data interface for integrating the simulation system into the intelligent traffic system, greatly make the data share and system integration more convenient.The model established in this paper can be applied to the traffic plans of big cities in China. Now the model has been applied in the city traffic management work in Shenzhen and it works well. The model has certain generalized value and reference value for the city plan and traffic construction in China's big cities.