HBIM AND THEMATIC MAPPING: PRELIMINARY RESULTS

Abstract. Geomatics' interest in Building Information Modelling (BIM) processes applied to Cultural Heritage is evolving in many directions. The traditional fields of Geomatics -data acquisition and processing- have been largely dealt with about HBIM (Historical Building Information Modelling) systems, but there are still some issues that need to be explored in more detail. In addition to modelling, it is essential to consider the information content of the model, how it is generated, recorded and managed.

If the objective of the HBIM model is the conservation project, it becomes essential to understand what types of data can be inserted in the model, how to record them and, above all, what their purpose is. The HBIM approach did not start out as a simple data repository, but as an information tool with the aim of helping the designer at all stages of the construction process. Moving to the field of preservation, much information about the building is represented by thematic maps. They allow to have a graphical image of the state of conservation of a façade or to understand the structural situation of a building.

This research, tested on the Arch of Augustus in Aosta, starts from the big amount of data acquired by the RAVA Laboratory of the Superintendency of Aosta during a long period. These data allowed to test different approaches to thematic mapping, according to the specific themes to be represented (previous restoration interventions, diagnostics, decay mapping, etc). Anyway, this experiment also required a theoretical reasoning that preceded the operational phases. Faced with a new system, in fact, it is always advisable to reason about the method applied, to avoid the error of simply translating a method that could instead be developed in new directions. The question, to which this article wants only to begin answering, concerns the role of thematic mappings in the preservation design made by a HBIM approach, their necessity and their implementation towards a truly three-dimensional data, which thus maintains all the information that is acquired directly in three dimensions and which instead, today, are reprojected in 2D or used as a placeholder in the 3D space.