Extending CityGML for IFC-sourced 3D city models

Differences in the scope and intent of the contrasting IFC and CityGML data formats entail that converting the former to the latter results in loss of information. However, for some use cases it is beneficial to keep also particular information from IFC that is not native to CityGML, and achieving that requires mechanisms such as the CityGML Application Domain Extension (ADE). We develop an ADE to support retaining relevant information from IFC. Besides being driven by the particular source of the input data (IFC), this multi-purpose ADE is shaped after a discovery process that involved examining potentially applicable use cases in Singapore, doubling as an extension that is adapted to a set of use cases and the local geographic context. We implement the conceptual work by generating an enriched dataset (with an automatic conversion from IFC to CityGML), visualising it, and discuss its added value in a use case.

Automated summary

The differences in scope and intent between IFC and CityGML data formats can result in information loss when converting from the former to the latter. However, in certain cases, retaining specific information from IFC that is not native to CityGML can be beneficial, requiring mechanisms such as the CityGML Application Domain Extension (ADE). Our development of an ADE to support retaining relevant information from IFC was driven by a discovery process involving potentially applicable use cases in Singapore and shaped to adapt to a set of use cases and the local geographic context.