From 3D GIS to ArcheoGIS: first steps towards a timeless conceptual model

In the last decades, Geographical Information Systems (GIS) have shown their potential to uncover spatio-temporal relationships between various objects and layers. Although archeologists have more and more utilized these techniques to analyze and interpret relationships between features on site, a full understanding of the possible advantages of the technology is for many still lagging behind. This shows the need to develop a comprehensive GIS for archaeological data which is not only cost-efficient and easy to use, but above all tailored to the requirements of people dealing with archaeological data in the field or as a primary source of information. It is clear that a three-dimensional GIS for archaeologists could hold many advantages over the traditional GIS tools which are mainly oriented towards a 2D representation and analysis of objects in a single time-frame. 3D visualizations have already proven to be valuable tools to record the state of a site and later revisit it in a virtual environment, long after it has been destroyed or heavily altered. Even more importantly, having a 3D overview of the different structures and objects on a site allows for topological and spatial analysis and a better understanding of the relations between the different excavated objects and stratigraphic layers. Overall, a 3D approach would not only enable new ways of handling this specific type of data but could be a starting point for new or improved methodologies all along the chain from fieldwork over analysis to reconstruction. Problems with developing such a system are mainly related to the broad diversity of archeological data and its inherent complexity. The data itself is intrinsically three-dimensional requiring a fully-fledged 3D GIS that is able to cope with the diversity in spatial, geometric and semantic information. Moreover, the temporal aspect that is linked to each of these information particles pushes the requirements even further towards a system that enables handling the fourth dimension and all its associated vagueness and fuzziness. In this project, we are currently examining the 3D relationships between structures and objects on several archeological sites. This should allow us to detect common characteristics that can be the subject of new or improved methods of 3D analysis that aren’t feasible in a 2D approach. Both these characteristics and the data model used to register and analyze them have an influence on the requirements for the development of a full 3D archeological GIS. Therefore, the first step is to identify the most significant characteristics, to implement them in an extensible data model and test its robustness in the analyses expected to be most commonly used. Since this research is part of a bigger project, the next steps should eventually result in a formal definition of a conceptual data model with a common archaeological vocabulary and semantic, geometric and topologic description of archaeological objects that will be put forward as an extension of the GML data structure