Research PaperTowards sustainable growth? A multi-criteria assessment of (changing) urban forms

- Landscape metrics were used to identify urban phases reflecting distinct socioeconomic contexts.
- The Attica's urban spatial structure has rapidly changed following Athens' expansion.
- Patch fragmentation, dispersion and shape complexity continuously increased over time.
- Athens' spatial structure of the early 1990s was more sustainable than earlier and more recent morphologies.
- Our results allow a better understanding of long-term form-function relationships in compact cities.

A multi-criteria approach based on descriptive, correlation and multivariate statistics and mathematical morphology was proposed to investigate long-term morphological changes in a metropolitan region (Attica, Greece) representative of the 'Mediterranean compact city' archetype. A total of 33 metrics measured at 6 time points (1948, 1975, 1990, 2000, 2006, 2012) from diachronic land-use maps were used to identify urban phases characterized by variable intensity of growth and reflecting distinct socioeconomic contexts at the local scale. The Attica's urban spatial structure has rapidly changed following Athens' expansion. Fragmentation, dispersion and shape complexity of built-up patches have been continuously increasing over time. Metrics' patterns differed significantly between two time intervals (1948-1990 and 1990-2012), with the highest spatial variability of landscape metrics being observed in the last two decades. Fractal indexes have reached the highest values in 2006 and 2012. Based on critical thresholds of per-capita land consumption, settlement dispersion and patch fragmentation, a Principal Component Analysis has indicated that the Athens' spatial structure of late 1980s and early 1990s was more sustainable than earlier and more recent urban morphologies. Results of this study contribute to a better understanding of long-term form-function relationships in compact and dispersed cities, offering an empirical base to identify sustainable urban forms.