The way towards land consumption: Soil sealing and polycentric development in Barcelona

This paper concerns the debate on polycentric development and land consumption in growing urban regions. The aim of this study is to verify if urban morphology reflects the transition from a mono-centric and hyper-compact form centred on Barcelona (Spain) towards a polycentric agglomeration based on subcentres functionally distinct from the head city. The spatial distribution of impervious land by municipal unit has been investigated under three spatial domains (province, metropolitan region and metropolitan area of Barcelona). Soil sealing indicators have been analysed using descriptive, inferential and multivariate statistical techniques. Sealing intensity and diversification decreased with the distance from the centre of Barcelona, while per-capita sealed land was low in the central city and much higher and stable in peripheral municipalities. Our results shed light on Barcelona’s long-term expansion, providing evidence in favour of settlement scattering instead of a genuine polycentric structure. The article finally debates the use of soil sealing indicators for the assessment of polycentric or scattered urban development in the Mediterranean region.