1. KIT – Universität des Landes Baden-Württemberg und nationales Forschungszentrum in der Helmholtz-Gemeinschaft Institut für Angewandte Informatik www.kit.edu IFC4 - Georeference

2. Institut für Angewandte Informatik 2 IFC Specification ENTITY IfcCoordinateReferenceSystem Name: OPTIONAL IfcLabel; Description: OPTIONAL IfcText; GeodeticDatum: IfcIdentifier; VerticalDatum: OPTIONAL IfcIdentifier; END_ENTITY; Examples: IFCCOORDINATEREFERENCESYSTEM('EPSG:25832','ETRS89 / UTM zone 32N','ETRS89',$); IFCCOORDINATEREFERENCESYSTEM('EPSG:4326','World Geodetic Datum 1984', 'WGS84',$); Andreas Geiger, Karl-Heinz Häfele 21.07.2014

3. Institut für Angewandte Informatik 3 IFC Specification Name: Name by which the coordinate reference system is identified. NOTE The name shall be taken from the list recognized by the European Petroleum Survey Group EPSG. Description: Informal description of this coordinate reference system. GeodeticDatum: Name by which this datum is identified. The geodetic datum is associated with the coordinate reference system and indicates the shape and size of the rotation ellipsoid and this ellipsoid's connection and orientation to the actual globe/earth. Examples for geodetic datums include: - ED50 - EUREF89 - WSG84 VerticalDatum: Name by which the vertical datum is identified. The vertical datum is associated with the height axis of the coordinate reference system and indicates the reference plane and fundamental point defining the origin of a height system. Examples for vertical datums include: - height above mean sea level at Dover in 1952 - other sea levels Andreas Geiger, Karl-Heinz Häfele 21.07.2014

4. Institut für Angewandte Informatik 4 Questions Name (optional) Identifier for the CRS Description (optional) Geodetic Datum (mandatory) Vertical Datum (optional) Combined EPSG code with vertical datum EPSG:5555 (ETRS89 / UTM zone 32N + DHHN92 height) Name  'EPSG:5555' Extra vertical datum EPSG:25832 + EPSG:5783 Name  'EPSG:25832;EPSG:5783‚ Examples: IFCCOORDINATEREFERENCESYSTEM('EPSG:25832','ETRS89 / UTM zone 32N','ETRS89',$); IFCCOORDINATEREFERENCESYSTEM('EPSG:4326','World Geodetic Datum 1984', 'WGS84',$); Andreas Geiger, Karl-Heinz Häfele 21.07.2014

5. Institut für Angewandte Informatik 5 OGC Example: urn:ogc:def:crs,crs:EPSG::25832,crs:EPSG::5783 ADV Example (German National Working Group): urn:adv:crs:ETRS89_UTM32*DE_DHHN92_NH Andreas Geiger, Karl-Heinz Häfele 21.07.2014