IFC (IFC4X3_ADD1) development IfcGeographicCRS Semantic definition

A IfcGeographicCRS is a non-Cartesian CRS that uses a three-dimensional ellipsoid surface to reference locations on the Earth as a latitude, longitude pair and the elevation above or below the ellipsoid. Entity inheritance Attributes

# Attribute Type Description
IfcCoordinateReferenceSystem (4)
1 Name OPTIONAL IfcLabel

Name by which the coordinate reference system is identified.

2 Description OPTIONAL IfcText

Informal description of this coordinate reference system

Example for ellipsoid: ELLIPSOID[,,,]

HasCoordinateOperation SET [0:1] OF IfcCoordinateOperation FOR SourceCRS

Indicates conversion between coordinate systems. In particular it refers to an IfcCoordinateOperation between this coordinate reference system, and another Geographic coordinate reference system.

WellKnownText SET [0:1] OF IfcWellKnownText FOR CoordinateReferenceSystem

Well Known Text (WKT) definition for this Coordinate Reference System inversely associated as a IfcWellKnownText entity.

Click to show 4 hidden inherited attributes Click to hide 4 inherited attributes
IfcGeographicCRS (3)
3 GeodeticDatum OPTIONAL IfcIdentifier

Name by which this datum is identified.

4 PrimeMeridian OPTIONAL IfcIdentifier

The identification of the meridian defining zero longitude in the used geographic CRS.

5 Unit OPTIONAL IfcNamedUnit

Unit of the coordinate tuple composing the coordinate system.

Table Formal propositions

Name Description

The map unit shall be given, if present, as a plane angle unit.

Table Formal representation

ENTITY IfcGeographicCRS
 SUBTYPE OF (IfcCoordinateReferenceSystem);
	GeodeticDatum : OPTIONAL IfcIdentifier;
	PrimeMeridian : OPTIONAL IfcIdentifier;
	Unit : OPTIONAL IfcNamedUnit;
	IsPlaneAngleUnit : NOT(EXISTS(Unit)) OR (Unit.UnitType=IfcUnitEnum.PLANEANGLEUNIT);
END_ENTITY; References

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