Street network analysis for understanding typology in cities: Case study on Sydney CBD and suburbs

Cities are networks of streets, places, people, systems, and their interactions. Network analysis has been extensively used in quantitative and economic geography, and transportation research. Methods such as the space syntax approach have also been used in urban design. More recent research in modeling cities as complex physical systems, and more specifically street networks as spatial networks, has shown that the network metaphor can provide global insight into city structure, the patterns of its growth, and how social and economic structures interact with spatial structures. Surprisingly, there exists almost no literature on mapping and analyzing the structure of Australian cities using the complex systems perspective. In this paper, we report on the network theoretic analysis street networks of Sydney CBD and suburbs. We generate primal graph representations of the fine scale structure of street networks, and use network metrics to measure and characterize the formal aspects of these networks. Through the results, we show that a surprising diversity of form exists even within what is understood as the same historical typology (say, grid layouts, or the garden city cul-de-sac). This study represents a first step in modeling an Australian city as a complex network. We relate the historical qualitative approaches of analysis of city structure to a network based quantitative approach, providing a mechanism for studying typology classification in city structure.