Underwater photogrammetry methods for a peculiar case-study: San Domenico (Prato), Italy

San Domenico Church (Prato, Tuscan, Italy) is a very peculiar case of terrestrial archaeology surveyed with underwater archaeological photogrammetric approach. The vault of the choir was completely filled by a very important numbers of potteries, which is very interesting building technique. To document this technique a complete photogrammetric survey was realized, layer by layer, following underwater archaeology system. It is interesting to note that in underwater archaeology such a case is quite rare, in fact or the wreck is in shallow water and the digging can be made (but this case is now unrealistic because in shallow water all the wreck have been stolen – or already excavated by archaeologist - !) or we are in deep water, with well conserved wreck but the depth doesn’t allow the excavation. In the last case only a surface survey is possible. Also for these reasons this particular case- study is very interesting in order to test underwater methods on real case. This experimentation is a good opportunity to develop and check methods, algorithm and software to obtain a relevant model of the site merging 3D measure and knowledge about the artefact as typology, theoretical model, spatial relationship between them. Even if this work started in 2006, with now obsolete digital camera and with a photographic campaign which not respect always the current constraints for building a dense cloud of point in photogrammetry,it is now used as a case-study for developing a relevant approach for underwater archaeology survey. Si presenta il peculiare caso-studio di San Domenico a Prato, la cui volta è stata costruita mediante le costipazione con vasi ceramici, secondo un sistema noto già nell'antichità. La documentazione grafica ha previsto l'uso di un rilievo fotogrammetrico sperimentale, grazie ad una pluriennale collaborazione con il LSIS (Cnrs-Marseille), mutuato da quello in uso per l'archeologia subacquea.