Research Of Road Network Analysis System Based On GIS

Road network analysis is of great importance in traffic planning and management. Road network analysis system based on GIS is an important way to realize visualization, which makes the analytical result more vivid and accurate, and accordingly lays the foundation for establishing policies and measures on traffic planning, constructing, management and control more effectively.Firstly, the thesis describes makeup and function of GIS and proposes the organizing of space data and attribute data based on GIS after studying the GIS data structure. The thesis suggests using vector data model to describe the road network because vector structure has advantage in representing network information. The space objects are stored in different layers to ensure the order. Large quantity of basic data including basic, transportation, transportation infrastructure and OD data are stored in the form of table as attribute data.Then, the thesis analyzes the road impedance function and shortest path algorithm. It gives two kinds of impedance functions, which are used in highway and city road respectively based on analysis of impedance function in common use. Expense and time are the two factors to influence the highway impedance and time is converted to expense. City road impedance is decided by time, which is sum of road travel time, intersection delay and turning penalty. Based on Dijkstra shortest path algorithm, the thesis suggests improvement in ways of simplifying the network and improving the algorithm itself. By transforming the intersection impedance to road impedance, the thesis solves the problem of Dijkstra shortest path algorithm not dealing with the node impedance.Finally, the thesis designs the road network analysis system initially by researching and analyzing framework and functions of the system. It consists of four parts which are system management, data management, graph management and road network analysis. GIS database and road network analysis based on GIS are the two main function of the system. The thesis also introduces the relative model including shortest path model, all or none assignment model, capacity restriction assignment model and static multi-path assignment model. It aims to give theoretic guidance to develop the system.