Understanding the Structure of Urban Bus Networks: The C-Space Representation Approach

摘要

The application of network science has greatly improved our understanding about the structure and properties of public transport network (PTN). Using tools and methods provided from network science, several standardized representations have been developed and analyzed to understand the topological structure of PTN from different aspects. In this paper, we present an empirical study on the bus network in Singapore. Different from previous studies based on a direct mapping of PTN on road networks, we focus on the weighted C-space representation of public transport networks to better characterize the interaction of different bus services. By exploring the statistical properties of this representation, we find that the bus network in Singapore exhibits similar patterns as many other cities in terms of distributions of edge weight, vertex degree and vertex strength. However, a superlinear scaling is found when we examine the dependency of a vertex's strength on degree, indicating that PTN in Singapore provides people with more alternatives to travel and transfer. The C-space representation also enables us to further explore the interactions between services by examining the community structure and the corresponding reverse mapping on road networks. This helps us to identify those crucial 'bridges' in a city, which is shared by different communities and connect diverse regions.