A Participative GIS approach to map and to model soil sealing in Padua

Soil sealing is, at present, one of the most important environmental issue in urban context. By the increasing of concrete surfaces and by the implementation of new buildings and urban infrastructures, soil sealing is directly and indirectly affecting soil system and related ecosystem services: carbon sequestration, microclimate regulation, hydrogeological risk mitigation, water and air purification. Even if the awareness of citizens about this theme is constantly increasing through both implementations of SDG and institutional tools, and glocal initiatives and networks such as the World Soil Day and People4Soil, there is still a lack of social processes for spatial data collection and generation. The general aim of this research is to involve university students to map the territory of Padua and to generate detailed spatial data about soil sealing in the city. The approach used is known as Participatory GIS (PGIS) and it brings GIS technologies to support public participation for a variety of applications by the inclusion and the empowerment of no expert population. In this way citizens, who generate spatial information, have the control, the comprehension and use of sensitive spatial data. In the present survey 25 volunteered university students, with different background and ages, were involved in the project and they were supervised by researchers which shared criteria and methodologies to extract geographical features from high resolution aerial images. The results obtained by the students were: 1) the detailed generation of spatial data about land cover in Forcellini, a residential neighbourhood of Padua of about 300 ha located in the east of the city centre, and the application of an ecological urban index named Biotope Area Factor (BAF) about the permeability of surfaces. Moreover, students performed a participative land use mapping, deepening spatial knowledge of the city in which they are living in, and increasing skills by open source GIS technologies in a collective learning environment.