4D reconstruction by multi-source data fusion: the case of the hidden Roman Circus in Milan

Gabriele Guidi, Laura Loredana Micoli, Umair Shafqat Malik

Abstract: Ancient city centers often contain traces of monuments which have almost entirely disappeared and whose few remains lie hidden beneath modern buildings. This is the case for many monumental buildings of the Roman period in Italian cities, which have vanished after having been gradually dismantled and their construction materials recycled, making room for modern structures. The knowledge of such monuments is often approximate and based on historical traces of various kinds. In such situations, 3D surveys and digital 3D modeling reconstructions can be of great help for scientific-archaeological research and for providing a scientifically supported image of cultural heritage sites. This paper shows the work on the emblematic example of the late Roman Circus of Milan, an impressive monument with dimensions of ca. 70 × 460 meters, built when Mediolanum served as capital of the Western Roman Empire (AD 286-402). Nowadays, this fact is unknown to most citizens of Milan. We developed a diachronic reconstruction approach to show the monument in its current state and its presumed past appearance. The reconstruction is based on a proper mix of quantitative data based on 3D surveys of its current condition, and on historical sources such as ancient maps, drawings, archaeological reports, laws regarding archaeological remains in the city and old photographs. In this project, the georeferenced acquired data of the remains played a crucial role for validating the previous reconstruction of the building and for defining some fixed points on which a reliable reconstruction covering different historical periods could be based.