An ontology-based rule mapping approach for integrating IFC and CityGML

Building information modeling (BIM) and geographic information system (GIS) are often integrated to achieve more refined urban management. Industry Foundation Classes (IFC) and City Geography Markup Language (CityGML) are widely used standards in BIM and GIS. The main problem of the transformation of these two standards lies in the gap between them in geometry and semantics. This article introduces an ontology-based rule mapping approach, achieving the transformation from IFC to CityGML through coordinate system conversion, geometric expression conversion, and semantic mapping. For semantic mapping, we have designed and established rules, enabling the effective mapping of the IFC model to the CityGML level of detail 0 (LOD0) to LOD4 model based on entities, appearance properties and building properties. To fully demonstrate the entire process, we give a detailed elaboration of the conversion of several IFC models.