IFC Georeferencing for OSM

Digital building models are increasingly available and used as sources to inform geospatial data sets. This poses the requirement to spatially locate building models in the geospatial context. In this paper, we present a case study on transferring georeference during conversion from digital building models in IFC (Industry Foundation Classes) to OpenStreetMap (OSM). First, we provide a condensed overview of how coordinates in IFC’s local engineering coordinate systems are related to geospatial reference systems with examples for different constellations. Second, we demonstrate a simple method to enrich IFC datasets with georeferences using existing OpenStreetMap outlines. In the third part we describe two substantially different methods to convert engineering coordinates into geospatial coordinates and show how these methods are implemented in two opensource software packages. Finally, we verify and compare the methods with a set of sample IFC and OSM data.