Digital models for archaeological documentation in urban context. 3D surveys in the new underground of Naples (Municipio station)

Excavations in multi-layered urban contexts, especially if aiming at the construction of important public infrastructures, present considerable difficulties in many aspects, including the timing to be respected, the various types of processing to be coordinated and, last but not least, the need to document a huge quantity of archaeological finds that frequently have to be demolished or removed to continue working. For these reasons, the rapid survey for the creation of a 3D model, as a virtual representation of the archaeological remains in a precise and realistic way, is certainly an excellent solution to achieve valid archaeological documentation. In this paper, therefore, we will present the specific problems faced in the 3D photogrammetric survey of an excavation area for the construction of the new underground station Municipio in Naples, investigated and documented in different periods. In particular, we will describe the methodology developed, the integration of the old digital model with the one realized through new technologies and, finally, the methods chosen to allow usability of this monumental complex, which no longer exists, by the general public.