LOW COST DIGITAL PHOTOGRAMMETRY FOR UNDERWATER ARCHAEOLOGICAL SITE SURVEY AND ARTIFACT ISERTION. THE CASE STUDY OF THE DOLIA WRECK IN SECCHE DELLA MELORIA-LIVORNO-ITALIA.

In the frame of the new ‘CIPA, Heritage, Documentation’ task group dedicated to underwater photogrammetry three laboratories from different disciplines have started to work together. We present here a work in progress on an underwater excavation of a Roman imperial wreck located in Secche della Meloria, in front of Livorno, Italy. Secche della Meloria have always represented a tough peril for sailing, but also a due passage in Northwestern Tyrrenian courses, with a particular regard for those around Portus Pisanus. The surveys led by Soprintendenza per i Beni Archeologici della Toscana (Nucleo Operativo Subacqueo) from 1993 to nowadays, enabled to localize two Roman imperial wrecks (among the other findings), conventionally named Meloria B and C, or Dolia Wreck and Marbles Wreck. The Dolia Wreck, situated at the center of the Secche, shows a concentration of dolia wall and lip fragments spread on about 9x6 meters area, part on the sand bottom and part hidden by posidonia (Posidonia oceanica) bushes at 6 meters depth. The larger fragments concentration is placed close by the posidonia, whose roots reach 2 meters height, maybe hiding part of the cargo load; other dolia large fragments have been found under a thin sand layer, close by the posidonia. Hull plank wooden elements showed up under a lip fragment; they seem to be also under the ware concentration. The Soprintendenza per i Beni Archeologici della Toscana is starting the archaeological excavation with a three-dimensional modeling program of this site. Three main goals were followed in this work. The first one is to record data before the next step of the excavation, which will be surely destructive. The photogrammetric approach is particularly relevant by the use of both geometrical data and qualitative data coming from the use of the photograph. The second goal is to insert, in the three D model obtained, three D representation of some dolia large fragments currently not present on the site for different reasons and, on the other hand, to insert some representation of entire dolia funded both on some measured fragment and archaeological hypothesis regarding the dolia classification. The third goal is to obtain a three D representation of the site usable as an interface between geometrical representation and a large set of archaeological data. -