The instruments and methods of investigation for the knowledge of architectural artefacts, thanks to the rapid evolution of technologies like the 3D laser scanner, new topographical tools (range-based modelling) and digital photogrammetry (image-based modelling) have seen considerable advances in the last decade. In particular the coordinated use of such technologies, by giving life to an integrated digital methodology, is capable of providing highly accurate three-dimensional architectural models. In the last years many questions have been asked about the relationship between the quantity and the quality of the data obtained with the various instrumental survey methods, and about their interaction and integration through completely digital procedures in continuous and rapid evolution; the ever-more frequent use of the new technologies in survey operations has increased the separation between the (objective) phase of information acquisition and a second, interpretative phase of data restitution through the creation of traditional or I.T.-based models. The acquisition phase, the survey’s more scientific phase as it were, is often strongly conditioned, however, by a series of factors that we might label instrumental and environmental factors. The former are those bound up with the knowledge of the operators of the tools and management software, while the latter are those linked to the object of the survey, to its internal and external conformation and its positioning in a specific context. A particular area in which environmental factors have a significant weight is that related to the surveying of ancient bridges, the extant testimony to which ties them to archaeology, and the knowledge of which is pervaded by multiple meanings, from both the archaeological and the architectural perspectives, but also as strategic testimony of an environmental context almost always transformed in its outline but stable in its constitutive elements (the levels of foundation and connection). The ancient bridge, and above all that connecting the two banks of a river, is often a difficult object to survey precisely for the specificity of the external environmental factors touched on above. The case studies examined in the Lusitania region – the bridges of Alconetar, Alcantara, Segura and Vila Formosa – represent unique instances for their current state of conservation and especially for the topographic and orographic complexity of their position, which makes the planning of the three-dimensional survey extremely complicated. In this sense, at present we do not have at our disposal architectural surveys of these edifices elaborated with a single methodology and with the same parameters of graphic feedback. The processing operations presented will be fundamental for the reconstruction of the historical processes of the bridges cited and for the archaeological study of the building technology employed in their construction. In particular, the chance that the new I.T. systems offer to document, with remarkable accuracy, geometries that are highly complex and at times, as in these cases, not directly surveyable with traditional methods, enables an accurate stratigraphic reading of the building units, the identification and checking of the structural deformations, and the salvaging and conservation of the historical artefacts with potential simulations of virtual anastylosis.

Resumen del póster presentado a la 43rd Computer Applications and Quantitative Methods in Archaeology Conference, celebrada en Siena (Italia) del 30 de marzo al 3 de abril de 2015.

Peer Reviewed