8.18.3.2 IfcCoordinateReferenceSystem
ABSTRACT This definition may not be instantiated
8.18.3.2.1 Semantic definition
The IfcCoordinateReferenceSystem is a definition of a coordinate reference system by means of qualified identifiers only. The interpretation of the identifier is expected to be well-known to the receiving software.
The unambiguous identifier by which the coordinate reference system is know, is stored in the Name attribute. Well defined identifiers include the geodetic and often also the vertical datum. In these cases the GeodeticDatum and the VerticalDatum can be omitted.
8.18.3.2.2 Entity inheritance
8.18.3.2.3 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. |
|
8.18.3.2.4 Formal propositions
| Name | Description |
|---|---|
| NameOrWKT |
No description available. |
|
|
8.18.3.2.5 Formal representation
ENTITY IfcCoordinateReferenceSystem
ABSTRACT SUPERTYPE OF (ONEOF
(IfcGeographicCRS
,IfcProjectedCRS));
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
INVERSE
HasCoordinateOperation : SET [0:1] OF IfcCoordinateOperation FOR SourceCRS;
WellKnownText : SET [0:1] OF IfcWellKnownText FOR CoordinateReferenceSystem;
WHERE
NameOrWKT : (HIINDEX(WellKnownText) = 1) OR EXISTS(Name);
END_ENTITY;