IFC 4.3.0.1 (IFC4X3) development

4.10.4 Project Global Positioning

Adding a geospatial coordinate reference to the geometric representation context using a recognized coordinate reference system (CRS). This allows to position the project coordinate system on Earth (normally using eastings, northings, elevation above horizontal and vertical datums, and orientation).

The following diagram shows the generic classes and relationships used when applying this concept. In addition, concepts may have particular importance to common or standardised industry practices and scenarios. For these specific usage scenarios, the tables below shows a recommended list of general usage patterns that users may adopt.

G IfcContext IfcContext 1. GlobalId [1:1] 2. OwnerHistory [0:1] 3. Name [0:1] 4. Description [0:1]      HasAssignments [0:?]      Nests [0:1]      IsNestedBy [0:?]      HasContext [0:1]      IsDecomposedBy [0:?]      Decomposes [0:1]      HasAssociations [0:?] 5. ObjectType [0:1] 6. LongName [0:1] 7. Phase [0:1] 8. RepresentationContexts [1:?] 9. UnitsInContext [0:1]      IsDefinedBy [0:?]      Declares [0:?] IfcGeometricRepresentationContext IfcGeometricRepresentationContext 1. ContextIdentifier [0:1] 2. ContextType [0:1]      RepresentationsInContext [0:?] 3. CoordinateSpaceDimension [1:1] 4. Precision [0:1] 5. WorldCoordinateSystem [1:1] 6. TrueNorth [0:1]      HasSubContexts [0:?] HasGlobalPosition      HasCoordinateOperation [0:1] IfcContext:RepresentationContexts1->IfcGeometricRepresentationContext:IfcGeometricRepresentationContext0 IfcLabel_1 IfcLabel IfcContext:Phase1->IfcLabel_1:IfcLabel0 IfcLabel_2 IfcLabel IfcContext:ObjectType1->IfcLabel_2:IfcLabel0 IfcLabel_3 IfcLabel IfcContext:LongName1->IfcLabel_3:IfcLabel0 IfcMapConversion IfcMapConversion 1. SourceCRS [1:1] 2. TargetCRS [1:1] Eastings 3. Eastings [1:1] Northings 4. Northings [1:1] OrthogonalHeight 5. OrthogonalHeight [1:1] XAxisAbscissa 6. XAxisAbscissa [0:1] XAxisOrdinate 7. XAxisOrdinate [0:1] 8. Scale [0:1] 9. ScaleY [0:1] 10. ScaleZ [0:1] IfcGeometricRepresentationContext:HasCoordinateOperation1->IfcMapConversion:SourceCRS0 IfcLengthMeasure_0 IfcLengthMeasure IfcMapConversion:Eastings1->IfcLengthMeasure_0:IfcLengthMeasure0 IfcLengthMeasure_1 IfcLengthMeasure IfcMapConversion:Northings1->IfcLengthMeasure_1:IfcLengthMeasure0 IfcLengthMeasure_2 IfcLengthMeasure IfcMapConversion:OrthogonalHeight1->IfcLengthMeasure_2:IfcLengthMeasure0 IfcReal_0 IfcReal IfcMapConversion:XAxisAbscissa1->IfcReal_0:IfcReal0 IfcReal_1 IfcReal IfcMapConversion:XAxisOrdinate1->IfcReal_1:IfcReal0 IfcReal_2 IfcReal IfcMapConversion:Scale1->IfcReal_2:IfcReal0 IfcProjectedCRS IfcProjectedCRS CRSName 1. Name [1:1] 2. Description [0:1] 3. GeodeticDatum [0:1] 4. VerticalDatum [0:1]      HasCoordinateOperation [0:1] 5. MapProjection [0:1] 6. MapZone [0:1] 7. MapUnit [0:1] IfcMapConversion:TargetCRS1->IfcProjectedCRS:IfcProjectedCRS0 IfcLabel_0 IfcLabel IfcProjectedCRS:Name1->IfcLabel_0:IfcLabel0 IfcText IfcText IfcProjectedCRS:Description1->IfcText:IfcText0 IfcIdentifier_0 IfcIdentifier IfcProjectedCRS:GeodeticDatum1->IfcIdentifier_0:IfcIdentifier0 IfcIdentifier_1 IfcIdentifier IfcProjectedCRS:VerticalDatum1->IfcIdentifier_1:IfcIdentifier0 IfcIdentifier_2 IfcIdentifier IfcProjectedCRS:MapProjection1->IfcIdentifier_2:IfcIdentifier0 IfcIdentifier_3 IfcIdentifier IfcProjectedCRS:MapZone1->IfcIdentifier_3:IfcIdentifier0
Figure 4.10.4.A

General Usage

ApplicableEntity
IfcContext
Table 4.10.4.B

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