How do you integrate BIM and GIS for infrastructure projects?

BIM-GIS integration challenges: different coordinate systems (local vs geographic), scale differences, data model incompatibilities, and semantic mapping. Workflow: establish project coordinate system early, define transformation parameters to national datum. IFC-to-geodatabase conversion preserves attributes. 3D city models (CityGML) bridge the gap. Use cases: site selection using GIS analysis with BIM for detailed design, clash detection with underground utilities, 4D simulation in geographic context, asset handover to facility management GIS. Tools: FME for data transformation, ArcGIS integration with Revit. Standards like InfraGML enable interoperability for linear infrastructure.