Analisi delle stratificazioni del paesaggio e valutazione del rischio archeologico nei territori di Barrali e Pimentel attraverso remote sensing e strumenti GIS open source

The object of this study is the history of the landscape, namely the history of the evolution of the relationship between man and land, as we can investigate it through the methods of landscape archaeology, with an approach defined as "global archaeology". The region studied, located in the municipal territories of Barrali and Pimentel, on the southern edge of the Trexenta area, is a natural crossroads between the historic regions of Parteolla, Campidano and Trexenta. The anthropic history of the region is characterised by a stable human presence which dates back at least to the fourth millennium BC, without interruption until the present day. This has meant that, despite the large amount of historical and archaeological evidence in the area, a relatively small number of archaeological emergencies remained in a good state of preservation. The historical-archaeological research work has been completed by the analysis of the current situation (intended uses underlined by urban plans and evaluation of specific risk factors) with the aim to understand the archaeological potential of the territory and to attempt an archaeological risk assessment. In this study, entirely conducted with open source software equipment (GIS QGIS software and SQLite/SpatialLite spatial database on Linux/Ubuntu platform), remote sensing and aerial photo-interpretation techniques and have been applied to the analysis of satellite images and aerial photographs, together with GIS methodologies for data archiving and analysis, with the creation of a spatial database and a matrix for the measurement of the potential and the archaeological risk from which thematic maps have been derived. Where possible, ground surveys were carried out for the integration of bibliographic, archive and remote sensing data, which provided information needed for the improvement of the reliability of the assessment of the potential and risk. In total, 46 sites have been catalogued for a period between the Neolithic and the Middle Ages, many of them were known through brief archive notes. The density of the sites shows a remarkable continuity of the settlement over the millennia and a prosperity derived by the solid agricultural economy of the region, traditionally centred around the cultivation of cereals. With the exception of a few particularly difficult times (such as the period between the end of the Judicial age and the Aragonese rule, and then later in the XVII century) which were marked by depopulation with the consequent abandonment of the settlements and the demographic crisis, the picture that comes out is that of small agricultural villages which were thoroughly and fairly uniformly spread in the flatter and more suitable areas for this type of economy. If we unfortunately don't know about any Neolithic settlements in the study area, except for an important site (Su Martaxiu) whose purpose cannot be interpreted with certainty, and we have to mainly refer to the necropolis data (among which the most important is that of S'Acqua Salida) in order to assess the density of the occupation of the territory. With regards to the Eneolithic period we have a single site (Is Pranus) that can be interpreted as a settlement. For the Nuragic period there are ruins of several nuraghis, that display the sophisticated control system of the territory and roads that is linked to an economy which is not only agricultural but also of a strong pastoral nature. Today, very little remains of the valleys' nuragic settlements with an agricultural economy, although several not yet archaeologically investigated examples are known (nuragic villages near the nuraghis of Santu Filippu and Santu Pedru). During the Punic and Roman periods, the area was densely populated. During the Punic age people used to live in small rural villages and farms, while in the Roman age also rustic villas became widespread in the countryside. The remains of these settlements have been completely dismantled as a consequence of the introduction of modern agricultural techniques, leaving only superficial dispersion. In this regard, ground surveys conducted near Barrali authorise to think about a settlement of considerable importance, and probably of remarkable continuity (the pottery found can be dated between the nuragic age and early Middle Ages). The research therefore has allowed to collect and synthesise in a diachronic way and to organise into a coherent framework a considerable amount of information on the area of study. Understanding the relationship between land, landscape and cultural heritage is in fact necessary in order to implement conscious and sustainable choices for territorial and urban planning and for preserving and promoting cultural heritage.