IfcGeographicElementType

Item	SPF	XML	Change	Description
IFC2x3 to IFC4
IfcGeographicElementType			ADDED

Semantic definitions at the entity

Entity definition

An IfcGeographicElementType is used to define an element specification of a geographic element (i.e. the specific product information, that is common to all occurrences of that product type). Geographic element types include for different types of element that may be used to represent information within a geographical landscape external to a building. Within the world of geographic information they are referred to generally as 'features'. IfcGeographicElementType's include:

point features such as seating, bus shelters, signage, trees;
linear features such as layby's;
area features such as ponds, lakes, woods and forests;
drainage such as catchment, reserver or outfall.

The specification of the specific types are given by the inherited attribute IfcElementType.ElementType given as an IfcLabel.

Geographic element types are frequently identified in feature catalogs that are produced for particular purposes. The IfcGeographicElementType entity enables the continued use of existing feature catalogs through capture of their identity and attributes.

Information from feature catalogs might be captured in various ways:

via property sets, some of which will be specifically defined within the IFC property set catalog whilst others will be created for local use; this is the form of capture that is expected to be most widely used
through use of the IFC classification model whereby features might be identified through an IfcClassificationReference with additional description; in which case, any further attributes required would still need to be captured in property sets.

NOTE This is due to the range of choices of element type thyat are available and their expression in different languages. It is not considered possible to create a reasonably full list of types within an enumeration. It is suggested that selection of the relevant type be drawn from an available 'feature catalog'.

HISTORY New entity in IFC4.

Attribute definitions

#	Attribute	Type	Cardinality	Description	C
10	PredefinedType	IfcGeographicElementTypeEnum	[1:1]	Predefined types to define the particular type of the geographic element. There may be property set definitions available for each predefined type.	X

Formal Propositions

Rule	Description
CorrectPredefinedType	The inherited attribute ElementType shall be provided, if the PredefinedType is set to USERDEFINED.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	C
IfcRoot
1	GlobalId	IfcGloballyUniqueId	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[0:1]	Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE only the last modification in stored - either as addition, deletion or modification.	X
3	Name	IfcLabel	[0:1]	Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.	X
4	Description	IfcText	[0:1]	Optional description, provided for exchanging informative comments.	X
IfcObjectDefinition
	HasAssignments	IfcRelAssigns @RelatedObjects	S[0:?]	Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.	X
	Nests	IfcRelNests @RelatedObjects	S[0:1]	References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).	X
	IsNestedBy	IfcRelNests @RelatingObject	S[0:?]	References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).	X
	HasContext	IfcRelDeclares @RelatedDefinitions	S[0:1]	References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.	X
	IsDecomposedBy	IfcRelAggregates @RelatingObject	S[0:?]	References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).	X
	Decomposes	IfcRelAggregates @RelatedObjects	S[0:1]	References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).	X
	HasAssociations	IfcRelAssociates @RelatedObjects	S[0:?]	Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.	X
IfcTypeObject
5	ApplicableOccurrence	IfcIdentifier	[0:1]	The attribute optionally defines the data type of the occurrence object, to which the assigned type object can relate. If not present, no instruction is given to which occurrence object the type object is applicable. The following conventions are used: The IFC entity name of the applicable occurrence using the IFC naming convention, CamelCase with IFC prefix It can be optionally followed by the predefined type after the separator "/" (forward slash), using uppercase If one type object is applicable to many occurrence objects, then those occurrence object names should be separate by comma "," forming a comma separated string. EXAMPLE Refering to a furniture as applicable occurrence entity would be expressed as 'IfcFurnishingElement', refering to a brace as applicable entity would be expressed as 'IfcMember/BRACE', refering to a wall and wall standard case would be expressed as 'IfcWall, IfcWallStandardCase'.	X
6	HasPropertySets	IfcPropertySetDefinition	S[1:?]	Set ~~list~~ of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type.	X
	Types	IfcRelDefinesByType @RelatingType	S[0:1]	Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type.	X
IfcTypeProduct
7	RepresentationMaps	IfcRepresentationMap	~L[1:?]	List of unique representation maps. Each representation map describes a block definition of the shape of the product style. By providing more than one representation map, a multi-view block definition can be given.	X
8	Tag	IfcLabel	[0:1]	The tag (or label) identifier at the particular type of a product, e.g. the article number (like the EAN). It is the identifier at the specific level.	X
	ReferencedBy	IfcRelAssignsToProduct @RelatingProduct	S[0:?]	Reference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product type.	X
IfcElementType
9	ElementType	IfcLabel	[0:1]	The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute 'PredefinedType' is set to USERDEFINED.	X
IfcGeographicElementType
10	PredefinedType	IfcGeographicElementTypeEnum	[1:1]	Predefined types to define the particular type of the geographic element. There may be property set definitions available for each predefined type.	X

Definitions applying to Common Use Definitions

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Common Use Definitions
	Revision Control	Common Use Definitions
IfcTypeProduct
	Product Type Shape	Common Use Definitions

Formal representations

XSD Specification

 <xs:element name="IfcGeographicElementType" type="ifc:IfcGeographicElementType" substitutionGroup="ifc:IfcElementType" nillable="true"/>

 <xs:complexType name="IfcGeographicElementType">

  <xs:complexContent>

   <xs:extension base="ifc:IfcElementType">

    <xs:attribute name="PredefinedType" type="ifc:IfcGeographicElementTypeEnum" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcGeographicElementType

 SUBTYPE OF (IfcElementType);

  PredefinedType : IfcGeographicElementTypeEnum;

 WHERE

  CorrectPredefinedType : (PredefinedType <> IfcGeographicElementTypeEnum.USERDEFINED) OR
((PredefinedType = IfcGeographicElementTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcElementType.ElementType));
END_ENTITY;

 EXPRESS-G diagram

Link to this page

	Geographisches Objekt - Typ
	Geographic Element Type
	Type d'élément géographique