Integrating parametric and non-parametric multivariate analysis of urban growth and commuting patterns in a European metropolitan area

Mono-centric regions have experienced a progressive transformation towards polycentric structures. Transition to discontinuous and dispersed spatial configurations was particularly evident in formerly compact and dense European cities, as a result of increasingly complex commuting patterns. Under the hypothesis that central locations have a balanced rate of resident population to internal workers and attract workers from neighbouring places, a multivariate analysis of commuting patterns may reveal latent transformations of compact, mono-centric cities towards polycentrism and settlement scattering. A more comprehensive understanding of the intimate nature and implications of urban transitions taking place in the last decades in Athens (Greece), a representative metropolitan region in southern Europe, was carried out using census data analyzed through a framework integrating descriptive statistics and mapping, multivariate exploratory data analysis, non-parametric inference and regression models. The analytical framework was proposed with the aim to assess commuting patterns vis à vis urban hierarchy in a context of (more or less) de-centralized growth. Empirical results for the study area indicate the persistence of a bi-centric spatial structure gravitating on the central cities of Athens and Piraeus, with early formation of employment sub-centres and local-scale alterations of the mono-centric scheme as a result of discontinuous urban expansion. Exurban development was associated with the formation of self-contained sub-centres with an increasing proportion of workers in total resident population.