Articles by Pierre Drap

In this paper we present an interdisciplinary project which is a work in progress towards a 3D Geographical Information System with a specific focus application on the Castle of Shawbak. The Shawbak archaeological project is a specific and integrated project between medieval archaeological research and computer vision done thanks a long-term cooperation between University of Florence and LSIS/CNRS Marseille. Focusing mainly on stratigraphical analysis of upstanding structures we conducted a survey using photogrammetry, both in a traditional way and using the most advanced techniques to obtain a dense map, and then a tool for statistical analysis. The photogrammetric survey is driven directly by archaeological data which is formalized by ontologies as a link between all the archaeological concepts which are surveyed. The 3D GIS is the last step of this chain and aims at the automatic production of 3D models through archaeological database queries: these 3D models are, in fact, a graphic image of the database and at the same time the interface through which the user is able to modify it and produce different kinds of analysis.

The ‘Progetto Shawbak. Ricerca, conservazione e valorizzazione del Crac’ de Montreal is a multidisciplinary project conducted by the Florence University Chair of Medieval Archaeology. An important objective of the work, pursued with the collaboration of Dr. Pierre Drap, Chargé de recherche at CNRS LSIS UMR 6168, is the realization of a 3D archaeological information system to manage a big amount of textual and graphic data. For this reason we tried to create a system that could handle all archaeological data in a single database that allows us to connect the 3D information derived from photogrammetric surveys with other archaeological records. Showback system is being tested on some Shawbak castle upright structures, including the huge Ayyubid Palace and a second site at the gate wall, and it aims to achieve the production of 2D and 3D representations through the queries it answers. This approach can obtain 3D representations of issues (e.g. possibility to see the USM of a particular phase in all analyzed buildings of the site) as well as new archaeological analysis (the development of quantitative analysis on the use of materials, the possibility of obtaining chronological data of the bricks, etc.). Finally, this research has led the Italian-French team to discuss the physics and stratigraphic relations at the basis of the Harris matrix.

Underwater archaeology has to depend on reliable and precise readings with limitations of access sometimes requiring an analysis and data interpretation on the site. In order to create optimal study conditions, the production of a virtual facsimile was planned. As part of the VENUS (Virtual ExploratioN of Underwater Sites) project, a procedure combining photogrammetry and ontological definition of artifacts was elaborated. These objects, essentially amphorae, are numerically modelled and viewed from photogrammetric measures taken on the site. 2D and 3D reconstructions are then obtained in standard GIS format.

The Petra monumental site is located on the left rim of the Rift Valley in central-southern Jordan. The entire valley, which is tectonic in origin, rests on Late Cambrian quartzarenite rock formations of continental origin. Past research conducted by our team has allowed us to identify the following main causes of the weathering processes: thermal expansion and shrinkage of rocks caused by the great differences in day and night temperatures contribute to the loosening of quartz grains that lead to the disintegration of the rock. Heavy rainfall and above all surface runoff contribute significantly to the removal of weathered materials from the surface. Other forms of decay are caused by the presence of salts along the fractures. Both fieldwork and laboratory analyses performed in the past in a climate chamber have demonstrated that the products usually used in conventional restoration work are not very effective, due to the “extreme” climate and the chemical and physical characteristics of the rocks. The project proposes the realization of a GIS aimed at acquiring complete knowledge of the man-made structures and hydraulic system underlying the routes of the canalisations and identifying the cisterns. This work is meant to contribute a valid support aimed at the restoration, which will involve several different disciplines, including the geological and chemical analysis of the rocks, the topography and the 3D photogrammetry.