IfcMapConversion

Natural language names
Konvertierung in kartographische Koordinaten
Map Conversion
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4 4.0.0.0
    IfcMapConversionADDED
IFC4x3_RC2 to IFC4x3_RC3
    IfcMapConversion
      ScaleYMODIFIEDInstantiation changed to OPTIONAL.
      ScaleZMODIFIEDInstantiation changed to OPTIONAL.
Semantic definitions at the entity
Entity definition

The map conversion deals with transforming the local engineering coordinate system, often called world coordinate system, into the coordinate reference system of the underlying map.

NOTE  The IfcMapConversion does not handle the projection of a map from the geodetic coordinate reference system.

The map conversion allows to convert the local origin of the local engineering coordinate system to its place within a map (easting, northing, orthogonal height) and to rotate the x-axis of the local engineering coordinate system within the horizontal (easting/westing) plane of the map.

NOTE  The z axis of the local engineering coordinate system is always parallel to the z axis of the map coordinate system.

The scale factor can be used when the length unit for the 3 axes of the map coordinate system are not identical with the length unit established for this project (see IfcProject.UnitsInContext), if omitted, the scale factor 1.0 is assumed.

HISTORY  New entity in IFC4

Attribute definitions
#AttributeTypeCardinalityDescription G
3EastingsIfcLengthMeasure Specifies the location along the easting of the coordinate system of the target map coordinate reference system.
NOTE  for right-handed Cartesian coordinate systems this would establish the location along the x axis.
X
4NorthingsIfcLengthMeasure Specifies the location along the northing of the coordinate system of the target map coordinate reference system.
NOTE  for right-handed Cartesian coordinate systems this would establish the location along the y axis
X
5OrthogonalHeightIfcLengthMeasure Orthogonal height relativ to the vertical datum specified.
NOTE  for right-handed Cartesian coordinate systems this would establish the location along the z axis
X
6XAxisAbscissaIfcReal? Specifies the value along the easting axis of the end point of a vector indicating the position of the local x axis of the engineering coordinate reference system.
NOTE 1 for right-handed Cartesian coordinate systems this would establish the location along the x axis
NOTE 2 together with the XAxisOrdinate it provides the direction of the local x axis within the horizontal plane of the map coordinate system
X
7XAxisOrdinateIfcReal? Specifies the value along the northing axis of the end point of a vector indicating the position of the local x axis of the engineering coordinate reference system.
NOTE 1 for right-handed Cartesian coordinate systems this would establish the location along the y axis
XAxisAbscissa it provides the direction of the local x axis within the horizontal plane of the map coordinate system.
X
8ScaleIfcReal? Scale to be used, when the units of the CRS are not identical to the units of the engineering coordinate system. If omited, the value of 1.0 is assumed. X
Formal Propositions
RuleDescription
TargetCRSProjectedIfcCoordinateOperation.TargetCRS is of type IfcGeographicCRS.
ValidXAxisBoth XAxisAbscissa and XAxisOrdinate must not be zero.
Inherited definitions from supertypes
Entity inheritance IfcMapConversionScaled IfcCoordinateOperation
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcCoordinateOperation
1SourceCRSIfcCoordinateReferenceSystemSelect Source coordinate reference system for the operation. X
2TargetCRSIfcCoordinateReferenceSystem Target coordinate reference system for the operation. X
IfcMapConversion
3EastingsIfcLengthMeasure Specifies the location along the easting of the coordinate system of the target map coordinate reference system.
NOTE  for right-handed Cartesian coordinate systems this would establish the location along the x axis.
X
4NorthingsIfcLengthMeasure Specifies the location along the northing of the coordinate system of the target map coordinate reference system.
NOTE  for right-handed Cartesian coordinate systems this would establish the location along the y axis
X
5OrthogonalHeightIfcLengthMeasure Orthogonal height relativ to the vertical datum specified.
NOTE  for right-handed Cartesian coordinate systems this would establish the location along the z axis
X
6XAxisAbscissaIfcReal? Specifies the value along the easting axis of the end point of a vector indicating the position of the local x axis of the engineering coordinate reference system.
NOTE 1 for right-handed Cartesian coordinate systems this would establish the location along the x axis
NOTE 2 together with the XAxisOrdinate it provides the direction of the local x axis within the horizontal plane of the map coordinate system
X
7XAxisOrdinateIfcReal? Specifies the value along the northing axis of the end point of a vector indicating the position of the local x axis of the engineering coordinate reference system.
NOTE 1 for right-handed Cartesian coordinate systems this would establish the location along the y axis
XAxisAbscissa it provides the direction of the local x axis within the horizontal plane of the map coordinate system.
X
8ScaleIfcReal? Scale to be used, when the units of the CRS are not identical to the units of the engineering coordinate system. If omited, the value of 1.0 is assumed. X
Formal representations
XML Specification
 <xs:element name="IfcMapConversion" type="ifc:IfcMapConversion" substitutionGroup="ifc:IfcCoordinateOperation" nillable="true"/>
 <xs:complexType name="IfcMapConversion">
  <xs:complexContent>
   <xs:extension base="ifc:IfcCoordinateOperation">
    <xs:attribute name="Eastings" type="ifc:IfcLengthMeasure" use="optional"/>
    <xs:attribute name="Northings" type="ifc:IfcLengthMeasure" use="optional"/>
    <xs:attribute name="OrthogonalHeight" type="ifc:IfcLengthMeasure" use="optional"/>
    <xs:attribute name="XAxisAbscissa" type="ifc:IfcReal" use="optional"/>
    <xs:attribute name="XAxisOrdinate" type="ifc:IfcReal" use="optional"/>
    <xs:attribute name="Scale" type="ifc:IfcReal" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcMapConversion
 SUPERTYPE OF(IfcMapConversionScaled)
 SUBTYPE OF (IfcCoordinateOperation);
  Eastings : IfcLengthMeasure;
  Northings : IfcLengthMeasure;
  OrthogonalHeight : IfcLengthMeasure;
  XAxisAbscissa : OPTIONAL IfcReal;
  XAxisOrdinate : OPTIONAL IfcReal;
  Scale : OPTIONAL IfcReal;
 WHERE
  TargetCRSProjected : 'IFCREPRESENTATIONRESOURCE.IfcProjectedCRS' IN TYPEOF(SELF\IfcCoordinateOperation.TargetCRS);
  ValidXAxis : (NOT EXISTS(XAxisAbscissa) AND NOT EXISTS(XAxisOrdinate)) OR
(NOT EXISTS(XAxisAbscissa) AND XAxisOrdinate <> 0.0) OR
(NOT EXISTS(XAxisOrdinate) AND XAxisAbscissa <> 0.0) OR
(EXISTS(XAxisAbscissa) AND EXISTS(XAxisOrdinate) AND NOT ((XAxisAbscissa = 0.0) AND (XAxisOrdinate = 0.0)));
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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