Research the influence of the ring road factor on route choice

Spatial relationships, which refer to the relationship among some geographical entities, are very important in geographic information systems. Involving the relations of topology, distance and direction, route choice problem is also the contents of spatial relationships. This paper aims to explore the ring roads impact on travelers when choosing routes in Beijing, and to provide a reference model of the route inquiry. Focusing on the 3^rd ring road in Beijing, we propose the Squares Model, which based on the framework of 12 orientation coordinates and the name of each sections of the 3^rd ring road. Based on the topological relationship between two-points and one closed curve, this paper analyze 18 kinds of typical topological relations between the squares and the start and end points of a route. It also studies the impact of ring road on travelers´ route choice through a cognitive experiment, in which the participants are members of the public in Beijing. The results show that the ring roads affect the travelers´ choice of the route up to a certain extent.