4-dimensional recording and visualization of urban archeological excavations

The new geomatic techniques and technologies for surveying an archeological excavation are not limited to obtaining more accurate data or more precisely geo-referenced positions on a map, as they can lead to new approaches and, indeed, raise the concept of different dimensions relating to the handled information. The techniques on offer are now fully 3D and, even more interestingly, can also permit to handle temporal information, that is, the evolution of operations over time. This allows scholars and technicians to build and maintain a wealth of vital knowledge documenting what happens during an excavation. This is further true when these are in urban areas, often known as “emergency excavations” from their distinctive logistics and timing constraints. The aim of this paper is to present, in a practical context, some of the many capabilities of 3D surveying performed through digital photogrammetry based on multi-view structure-from-motion approach in the field of urban emergency archeology. The information that can be derived from exploring three-dimensional models allows us to interact with realities that no longer exist, with the possibility not merely of recording their memory, but also of further studies and insights, even after a long period of time. In addition, the excavation itself is documented as it evolves, thus allowing the main phases of the process to be reconstructed retrospectively. The study case examined covers a small necropolis discovered in Rimini (Italy) in 2015. The results and the 3D final products can be managed through Geographic Information System (GIS) tools and, therefore, can easily be interfaced and integrated with other types of information on a different scale.