Giuseppina Vacca

A Spatial Information System (SIS) for the Architectural and Cultural Heritage of Sardinia (Italy)

The paper presents a spatial information system (SIS) developed in the research project, “Tecniche murarie tradizionali: conoscenza per la conservazione ed il miglioramento prestazionale” (Traditional building techniques: from knowledge to conservation and performance improvement), with the aim of archiving and managing the data derived from the project. The research project has the purpose of studying the building techniques of the 13th–18th centuries in the Sardinia region (Italy) for their knowledge, conservation, and promotion. The research is founded on a multidisciplinary approach involving several specialists integrating their expertise and providing their input to the knowledge of the dimensional, technical constructive, mensiochronological, materials, physical-mechanical, and energy performance features. This multidisciplinary approach is used to define the peculiarities and behavior of the examined structures, including their performance levels, and then direct the interventions toward innovative, mindful, and ethically correct solutions. The management of the huge amount of data produced during the research required the building of a SIS composed of a geodatabase connected to a GIS and a WebGIS through a Web Map Service (WMS). The entire infrastructure is developed and implemented using open source software components, and will make the research data available to the scientific and professional communities, both for further development and for technical uses. As of today, we surveyed and archived more than 500 buildings belonging to the Sardinia region architectural heritage, and classified them into four main macro categories: defensive architectures, religious architectures, residential architectures, and industrial architectures.

The Use of Nadir and Oblique UAV Images for Building Knowledge

This paper focuses on the processing and study of 3D models obtained from images captured by an unmanned aerial vehicle (UAV). In particular, we wanted to study the accuracy gains achieved in the surveying and the measurement, such as height, area, and volume, of the dimensions of the buildings in the 3D models obtained with both nadir and oblique UAV flights. These latter types of flights are particularly suitable for the 3D modeling of cities or urban agglomerations, where it is important to achieve a complete building reconstruction, including facades and footprints of buildings. For this purpose, several UAV surveys with both nadir and oblique axes were performed. The nadir flight acquired images over an area of about 3.5 hectares containing 30 buildings, while the second flight, performed with both a nadir camera and an oblique camera, was conducted on a single building. The images from the flights were processed with Photoscan software by Agisoft and with Pix4D, studying their different potentialities and functionality. The results were compared with the data from the 1:2000 scale Geotopographic Database (DBGT), with the results of a Global Navigation Satellite System (GNSS) survey and with 3D model from the Terrestrial Laser Scanner (TLS) survey. The obtained results have shown that oblique UAV flights increase the achievable accuracy both in terms of the number of points in a point cloud, and in the in measurements taken on the 3D models, with respect to the limited cost, and at the increase in time for surveying and image processing.

The Medieval San Francesco Convent in Cagliari: From the Architectural, Materical and Historical-Stratigraphical Analysis to the Information System

The Franciscan monastery, situated in the historic center of Cagliari (Sardinia), was founded in the thirteenth century, and transformed during the later centuries, up to the present day. The complexity of the case and the lack of objective data about its history has led us to carry out an interdisciplinary inquiry, in order to achieve a better knowledge of the building, preliminary for the drafting of a restoration project that respects all the signs that the time left. Starting from a deep examination of the indirect sources, turned out to be incomplete, the investigation continued with the execution of a survey with laser scanner and with the characterization of materials and related diseases of degradation.For the laser scanner survey we used a Faro Focus 3D, versatile and lightweight instrument that allows to perform scans with high speed point acquisition and high accuracy. For data elaboration we used the JRC 3D Reconstructor Software by the Gexcel srl.The characterization of the materials was perf...