The Domus of the Calendar: a quantitative comparison analysis of digital data obtained from 3D laser scanners, SFM methodologies, and portable devicesS

Data acquisition digital methodologies have become a reliable tool for surveying buildings with heritage values. Laser scanning has become the preferred method for performing 3D digital surveys because of its high accurate results; even though, the cost associated with it is usually high. Emerging technologies have been able to produce low-cost data acquisition methods, and they are currently being incorporated as part of digital survey projects. Using the Domus of the Calendar as a case study – an exceptionally unique archaeological and architectural site that was incorporated to the structural foundation system of the basilica of Santa Maria Maggiore – the present investigation aims to evaluate the data quality of two low-cost emerging technologies, namely SfM (Structure from Motion) and the iPad LiDAR system. This evaluation was developed by comparing low-cost technologies data acquisition capabilities with those of the laser scanner. The data for this test was obtained during an integrated survey campaign aimed at executing a critical analysis of the many historical layers of the Santa Maria Maggiore basilica. The results obtained from this investigation highlights the reliability of the different techniques implemented and suggest a useful solution for different and recurrent multi-scalar contexts.