An integrated survey system for the Nuraghe Sa Jua, Sardinia, Italy

The paper describes the results obtained following a three-dimensional survey on the Nuraghe Sa Jua in Aidomaggiore (west-Sardinia, Italy), in which two high-resolution methodologies - the Laser Scanner survey and the drone aerophotogrammetry - were integrated. The nuraghe’s documented problem pertains to the detachment of some wall ashlars near the stairwell, which may create a risk of structural collapse and subsequent loss of the archaeological asset. The main goal of the study is to ensure visitor’s safety, the conservation of the heritage site, and the enhancement of its value. The integrated survey serves as a first step towards a better understanding of the asset's safety requirements and architectural restoration. The accuracy of surveying by means of a 3D laser scanner was complemented with the use of drone digital photogrammetry, which enabled the surveying of areas that would otherwise have been inaccessible, whilst ensuring safety for the operators, the equipment, and the monument itself. A series of 2D graphic drawings were created using open-source software, producing high-quality 3D models and accurate orthophotos, which are measurable, and which can be easily interpreted by the client who commissioned the survey work. The results demonstrate the cost-effective advantages of using high-resolution techniques for archaeological conservation. • Surveys were carried out by TLS and digital drone photogrammetry • Direct and indirect measurements have been used to identify structural issues • This approach made it easy to plan and the interventions • Safety protocols during and after the restoration of the monument will be followed • HQ data processed can be easily shared and consulted by PA officers