Abstract: Current drainage network topology model is too simple to complete the spatial analysis for specific drainage business because of neglecting the details of the drainage network.To some extent,it hinderes the development of the drainage GIS system.Based on graph theory, the detailed topology model of urban drainage GIS system was presented in this paper.Firstly,on the basis of the object oriented method, topological concept model and logical model were put forward, which the detailed rules of the topological relation were increased so as to really simulate the objective world.In the design of data structure,orthogonal list was adopted as a storage structure,and it was also improved as well as linked with R⁺ tree in order to generate spatial index.During spatial analysis designing, the typical algorithm of spatial query and path analysis based on R⁺ index and orthogonal list was presented.With the example for development of Zhenjiang city drainage network geographic information system, the practice was carried out.Experiments show that the topology model proposed in this paper can better simulate the objective world,provide more spatial analysis, realize rapid access to huge data,and make a solution for efficient space analysis of city drainage system GIS that combined with huge data.

Key words: drainage GIS, spatial analysis, topology model, R⁺ tree, orthogonal list