ROADMAP FOR INTEROPERABLE 3D DATA MODELS IN OGC APIS AND OTHER DATA EXCHANGE APPROACHES

Abstract. Many data exchange standards for 3D spatial data applications exist, ranging from the general Geography Markup Language (GML) underpinning CityGML to specific models for business application domains, such as BuildingSMART Industry Foundation Classes (BIM/IFC). There are a number of different approaches to modelling 3D objects, and in general the geometry aspects of these can be readily understood in the context of the visualisation needs of different applications. The topology, or relationships between elements of these objects, on the other hand is either not directly supported by such geometry models or implemented in different ways by different standards. We discuss limitations of existing standards for describing topological relationships in particular. In some cases topology information is embedded in geometry objects using identifiers for vertices, edges and faces, but in general there is scope to develop a standardised model for describing alternatives for topology and 3D geometry representations. A limited set of such models allows for interoperability via transformations between different representations. The ISO 19107 Spatial Schema provides an adequate conceptual model for these concerns, so we present the argument that a profile of this comprehensive model be defined for the limited set of such representation options required for Smart Cities and other similar applications.