The periurban city: geostatistical methods for its definition

The expression “periurban area”, despite its large use, does not have a clear and unambiguous definition. Different points of view generate more barriers in determining the exact edge of these zones. These various approaches are due to the complexity of the phenomenon to be analyzed and to the huge variety of territorial contexts in which it may reveal. The phenomenon is characterized by an urban growth with soil consumption generating loss of competitiveness for agricultural activities. Some experiences, in a spontaneous way, take into account only proximity to urban areas. It is obvious that contiguity condition alone is not sufficient to define such a complex phenomenon. The aim of this paper is to define more precise rules in order to describe the periurban phenomenon, using techniques of spatial statistic and point pattern analysis. This approach has been tested in the case of study of Potenza Municipality. This area, about 18,000 ha wide, is located about 900 m a.s.l. and is characterized by a relevant presence of forests, very steep slopes and a large number of areas with geological instability phenomena. Our interest in this area especially comes after the earthquake of 1980, when a huge migration of inhabitants began towards the countryside around the Town of Potenza. It was so intense that it deeply altered the urban morphology and modified the traditional physical functional relationships between the town and the rural territory.