Level of Georeferencing - dd-bim/City2BIM GitHub Wiki

The software supports the concept of different levels of georeferencing. This can be read in the following paper: Paper; Presentation

IFCTerrain supports Level 30, Level 40 and Level 50.

• in general it is possible to choose different level (30/40/50)
• switch the input for Orgin between:
  • Calculate from dataset (default): place the coordinate origin in the middle of the total project area (XY) (z will be set to: 0)
  • *Custom origin): input the wanted X-, Y- and Z- values
• enable rotation to set a specific rotation (unit: deegres) (default: 0°)

• Referencing in entity IfcSite by:
  • IfcLocalPlacement
  • IfcAxis2Placement3D (Location (XYZ), Axis, RefDirection)

• Referencing in entity IfcProject by:
  • IfcGeometricRepresentationContext (include Rotation for True North)
  • IfcAxis2Placement3D (Location (XYZ), Axis, RefDirection)

Note: Only available above IFC2x3!

• Referencing in entity IfcProject by:

  • IfcGeometricRepresentationContext
  • IfcMapConversion (Location (xyz), Axis, RefDirection and Scale)
  • IfcProjectedCRS (include metadata)
    • MapProjection (EPSG)
    • MapZone
    • MapUnit (IfcSIUnit)

• in addition to Level 30/ 40: you can add:

  • scale (this means the geodetic scale!)
  • epsg code (to query the metadata): edit metadata via the button "edit metadata" the following metadata can be stored: