Topological Structure Evolution and Complexity of Urban-rural Road Network in Wuhan Metropolitan Area

Complexity is a measure of the level of organization of the system, when the system is compelled to be far away from the thermal equilibrium condition and enters the ordered state through self- organization, the complex structure appears frequently. As a typical, open and complex giant system, the transport network complexity research received a strong attention of various research areas. At present, the complex research of transport network mainly centralized in road network complex elementary theory(research direction and system), the topology of road network(scaling, small-world, reliability and centricity) as well as the kinetics process of road network. However, few efforts have been devoted to the complexity emergence of road network from dynamic process. Therefore, based on the urban-rural road network spatial databases of Wuhan urban agglomeration,this article systematically reveals the topological structure evolution and complexity emergence of urban-rural road network with the application of complex network theory. Urban-rural road network is a typical two-dimensional plane picture, lacking ofsuper planarity, and overall showing a similar characteristic of stochastic network. Urban-rural road network is a complex network which evolves between random network and regular network so that the whole road network demonstrates a performance of cross-coupling of the randomness and orderliness. Complexity evolution of urban-rural road network system is the result of the joint action of self-organization and hetero-organization mechanism, and the complexity emergence of urban-rural road network is a mutually alternate and ever-changing process in the function intensity, which was mainly influenced by the partial random disturbance and regularity regulation. Transportation network is the material conditions and prerequisites for forming the metropolitan area network system. It is also the main channel of material flow, energy flow and information flow which play important role in the socio-economic development of Wuhan metropolitan area. Urban-rural road network of Wuhan metropolitan area need to strengthen country road upgrading so as to enhance the external connectivity of the nodes. Simultaneously, the size of the node level should be increased and the structure of the road network should be further optimized. The purpose is to improve the clustering coefficient and accessibility of the road and make the road network evolved from tree net to net.