# 8.18.3.11 IfcProjectedCRS

AbRV ⓘ
RV ⓘ

## 8.18.3.11.1 Semantic definition

IfcProjectedCRS is a coordinate reference system of the map to which the map translation of the local engineering coordinate system of the construction or facility engineering project relates. The MapProjection and MapZone attributes uniquely identify the projection to the underlying geographic coordinate reference system, provided that they are well-known in the receiving application. The projected coordinate reference system is assumed to be a 2D or 3D right-handed Cartesian coordinate system, the optional MapUnit attribute can be used determine the length unit used by the map.

The unambiguous identifier by which the coordinate reference system is know, is stored in the inherited Name attribute. Well defined identifiers include the map projection and also the map zone information. In these cases the MapProjection and the MapZone attributes can be omitted.

## 8.18.3.11.6 Formal representation

ENTITY IfcProjectedCRS
SUBTYPE OF (IfcCoordinateReferenceSystem);
GeodeticDatum : OPTIONAL IfcIdentifier;
VerticalDatum : OPTIONAL IfcIdentifier;
MapProjection : OPTIONAL IfcIdentifier;
MapZone : OPTIONAL IfcIdentifier;
MapUnit : OPTIONAL IfcNamedUnit;
WHERE
IsLengthUnit : NOT(EXISTS(MapUnit)) OR (MapUnit.UnitType = IfcUnitEnum.LENGTHUNIT);
END_ENTITY;