Multiple Uses of a 3d Point Cloud: the Castle of Franchimont (province of Liège, Belgium)

This paper presents the identified obstacles, needs and selected solutions for the study of the medieval castle of Franchimont, located in the province of Liège (Belgium). After taking into account the requirements from all the disciplines at work as well as the problems that would have to be tackled, the creation of a 3D point cloud was decided. This solution would be able to deal with the characteristics and needs of a research involving building archaeology and related fields. The decision was made in order to manage all of the available data and to provide a common working tool for every involved cultural heritage actor. To achieve this, the elaboration of an Archaeological Information System based on 3D point clouds as a common virtual workspace is being taken into consideration. * Corresponding author INTRODUCTION The medieval castle of Franchimont (Province of Liège, Belgium) is currently being investigated under multiple angles. The origins of this cultural heritage site are not well known. Based on the written sources, two hypotheses have been established dating the beginning of the construction of the castle either to the tenth century or the eleventh century. Over the course of the next few centuries, the buildings were modified, partially destroyed and reconstructed and new structures were added. By the end of the eighth century, the castle was abandoned and its ruined state was officially recorded by a surveyor (Hoffsummer, 2016). The ruins of the castle of Franchimont quickly attracted artists and photographers. This allows for an important iconographic coverage documenting the successive stages of the destructions. Additionally, the beginning of the twentieth century marks the beginning of archaeological investigations: several researchers and various sectors have been studied. At the same time, restoration works have been undertaken where it was needed. For the last fifty years, the Compagnons de Franchimont, a notfor-profit association, has been taken care of archaeological investigations, restoration works and opening the site for visitors (Hoffsummer, 2016). The University of Liège has been implicated with the research carried out at the castle in various ways, e.g. excavations, building archaeology and topographical surveys (fig. 1). 1. CULTURAL HERITAGE ACTORS Since the creation of the Compagnons de Franchimont association, interventions have been undertaken regularly on the cultural heritage site. These may include excavations, restorations, reparations and adapting the site for tourist purposes. For these various actions, other than the association’s members, other actors working in the cultural heritage field have been involved. Figure 1. 3D point cloud of the castle of Franchimont, view from the north-west. The stairs are visible through transparency as they are located inside of the outer wall. However, these mostly punctual works have not always been recorded and the data was also not assembled into one common and global documentation system. This has led to multiple data collections that are not always available to other cultural heritage actors. 1.1 Archaeological investigations Several excavations and building archaeological studies have been carried out over the years. These are characterized by different numbering systems over the years, repeating numbers that do not refer to corresponding elements or a common stratigraphical level. Also, as the excavated sections have been filled in, current analysis can only be executed based on photographs taken during the digs, on plan and cross-section drawings as well as on the related excavations journals. However, it can be quite difficult to understand some of the theories and conclusions as they can hardly be verified on site. Also, the research on this castle is not over yet: new excavations should take place later this year. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2/W5, 2017 26th International CIPA Symposium 2017, 28 August–01 September 2017, Ottawa, Canada This contribution has been peer-reviewed. doi:10.5194/isprs-archives-XLII-2-W5-475-2017 475