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Time-Space Convergence in Urban Systems

Most studies of time-space convergence in urban systems have used Multi-Dimensional Scaling (MDS). However, two-dimensional configuration in these studies cannot be always regarded as geographic map, particularly for a long-term qualitative change. Q-analysis, a topological language, enables us to understand that change. The objective of this paper is considering methodologies of MDS and Q-analysis in time-space convergence studies.     Two studies of time-space convergence in Japan, Murayama's MDS and the author's Q-analysis, are compared from a methodological view. The MDS method reduces multi-dimensional metric space to two-dimensional one, but that tends to break original adjacent relationships. Q-analysis can describe the structure of topological relationships among cities, using the concepts of local dimensionality, nearness, and connectivity. While MDS focuses on the origin and distance, Q-analysis is applicable to a long-term uneven transportation development.