Study on the Formation and Evolvement Mechanism in the City System

In this paper we suppose the formation and evolvement mechanism of city system is the site selection of special entities in the city. We construct model to simulate the mechanism based on multi-agent system, the experiment results show that the distribution of a virtual city system can be generated by the mechanism. Further, we prove that the generated distribution of city system is corresponding to that of a real city system by validating with the Zipf law. The work can help to build the virtual city model.