Geographic Information Systems (G.I.S.) for the Analysis of Historical Small Towns

Introduction

The physical, anthropological, biological and ethnic backgrounds of a territory represent the most evident characteristics of its landscape . However, the perception of the landscape itself depends also on the observer and his life. In the European Landscape Convention, also known as Florence Convention, it is clearly established that landscape” means an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors” (European Community, 2000).

This agreement defines also a series of countermeasures that Member States should undertake for the recognition and safeguard of landscapes. In particular, the agreement contains the policies, objectives, the preservation and management of the landscape which is recognized as a fundamental component of the European heritage and a key element for ensuring the quality of life.

The safeguard of landscape is not dependent on generally prescribed standards of beauty or originality, being determined by peculiar aspects such as magnitude of the territory, cultural, environmental and social characteristics and, last but not least, historical frame. Some regions are in fact characterised by a unique combination of human and natural landscapes where many small historic towns are located in a peculiar geomorphology. Being aware that these centres are authentic “places of memory,” as they result from a slow economic and cultural process and preserve the identity of communities, each analysis is performed trying to relate each element of the cultural heritage to the surrounding natural and environmental context. These historical towns, most of which established during the medieval age, are often exposed to human factors of degradation including, among others, the risks of soil overexploitation and natural factors such as the physical vulnerability determined by considerable seismic and volcanic activities, and by the peculiar geomorphological and hydrogeological pattern of the territory. These risks need to be mitigated by means of a careful analysis of the criticity levels in the different geographical areas and by developing strategies based on requirements and operational guidance (Pelliccio, 2013).

Starting from the idea that a damage generally involves complex systems, with large numbers of variables, determining physical and social consequences, the risk assessment cannot be just started from statistic data or from the analysis of “harm post event.” The quantification of these criticity levels is based on a holistic analysis of the landscape, in which elements are regarded as open sets and continuous dynamic relationship are established among them. The holistic approach allows to analyze both the quality of the visual perception and the physical features and the cultural peculiarity of landscape or, in addition, all the factors which make these realities particularly vulnerable and prone to degradation.

In order to achieve this goal, an investigation procedure has been set up where the results of large and small scale analyses are included in a flexible and easy to use tool, able to combine information of different nature. The operational support for this study is provided by the information technology and, more specifically, by the Geographical Information Systems, nowadays considered as the most innovative tools to figure out and manage realities made of a variety of multiple factors. The information systems include more and more rigorous methods, to be differentiated according to the different scales of representation used to join dataset to geometric model of spatial shapes (Aspinal, 1999): the 3D capabilities of these systems, creates elementary or complex spatial shapes for the architectural or environmental models on which a multidisciplinary analysis can be performed. In this way, the Information Systems are valuable tools for the management, representation and visualization of heterogeneous data. They are able to control the transformation processes in which the landscape is continually subjected.

Concluding, the safeguard of landscape passes through the knowledge of a lot of environmental data and through its identification and monitoring, so the GIS are capable of quantifying the environmental quality in order to provide the local governmental agencies with maintenance plans where priorities are clearly defined.