Tracking 20 years of urban sprawl and policy gaps: the case of Cyclades islands, Greece

Urban sprawl represents a critical issue for island and coastal areas. In addition to the intense tourist development, the Cyclades islands also face issues related to the shortcomings and the way of implementation of spatial planning in Greece. This research endeavour seeks to offer a multitemporal quantitative depiction of the built-up area changes of the Cyclades through the utilization of remote sensing methodologies and geoinformatics tools for analysis. The analysis employs Landsat satellite images, spanning the period from 2000 to 2020, with a five-year interval. The Random Forest (RF) machine learning algorithm was selected for image classification. The results obtained demonstrate the significant changes that have occurred in the built-up area. The exurban area has been the focus of spatial metrics, which highlight the fragmentation, complexity and dispersion of the built-up area, indicating ad-hoc practices and the absence of integrated planning. An integrated, contemporary and consistent spatial planning should be implemented in order to counteract the dynamics of urban sprawl on the islands, which poses a significant threat to the distinctive and fragile landscape of the Cyclades, thereby jeopardizing the sustainable development of the region.