Semantic Approach to 3d Historical Reconstruction

Our work deals with the semantic 3D reconstruction of some rooms of Forte San Giorgio on Capraia Island (Livorno, Italy) excavated by the University of Pisa during the last summer. Data acquisition was achieved by total station and processed in order to generate a simple 3D dxf file for the schematic representation of the building; dxf is an “open format” and has a complete integration with xml language. Furthermore, dxf is readable by the major 3D data model software. To construct the model, we then imported the dxf into Blender, the most important and powerful 3D modelling open source software. First of all, by using Blender, we created a layer on which we put the real archaeological data gathered on field. Then, on another layer, we drew the hypothetical reconstruction. It was thus possible to export the file into SGJ-3D software and organize the layers according to the classes of CityGML, which is a profile application of GML designed for the semantic management of 3D features (buildings and its components like windows, roofs, walls, doors, etc.). The semantic structure is based on the relationship “is part of”; for each spatial element it is possible to assign an attribute in order to distinguish the feature’s reliability in the reconstruction process. SGJ-3D-software uses a database model and thus allows detailed description of object-oriented geographic data as well as mapping these data on the data scheme. All geographic data, attribute data and metadata are GML-structured. They are stored in objectrelational databases, that provide the basis for SGJ-3D. GML is based on XML, therefore all the spatial features are encoded in XML. It is possible to visualize the file by using specific software (Aristoles or LandeXplorer) and keeping the layer distinctions. Further, through XML-based web it is possible to perform queries in order to extract all required information concerning the model and its layers.