5.4.3.63 IfcSite
5.4.3.63.1 Semantic definition
A site is a defined area of land, possibly covered with water, on which the project construction is to be completed. A site may be used to erect, retrofit or turn down building(s), or for other construction related developments.
Precise geospatial information of a site shall be derived from the georeferencing entities that relate the IfcProject to the real world, using sets of datum (see IfcCoordinateOperation and IfcCoordinateReferenceSystem).
In small-scale projects (e.g., building), when georeferencing is not provided as recommended above, the Longitude, Latitude and Elevation attributes of IfcSite can be used for approximate indication of the site location. This methodology is not meant to replace precise georeferencing, but can still be useful for those use cases that do not require accurate geospatial information (e.g., sun shading simulations). If asserted, the Longitude, Latitude and Elevation establish the point in WGS84 where the point 0.,0.,0. of the LocalPlacement of IfcSite is situated.
The geometrical placement of the site, defined by the IfcLocalPlacement, shall be always relative to the spatial structure element, in which this site is included, or absolute, i.e. to the world coordinate system, as established by the geometric representation context of the project. The world coordinate system, established at the IfcProject.RepresentationContexts, may include a definition of the true north within the XY plane of the world coordinate system, if provided, it can be obtained at IfcGeometricRepresentationContext.TrueNorth.
A project may span over several connected or disconnected sites. Therefore site complex provides for a collection of sites included in a project. A site can also be decomposed in parts, where each part defines a site section. This is defined by the composition type attribute of the supertype IfcSpatialStructureElement which is interpreted as follow:
- COMPLEX = site complex
- ELEMENT = site
- PARTIAL = site section
Figure 5.4.3.63.A shows the IfcSite as part of the spatial structure. In addition to the logical spatial structure, also the placement hierarchy is shown. In this example the spatial structure hierarchy and the placement hierarchy are identical.

Figure 5.4.3.63.B describes the heights and elevations of the IfcSite. It is used to provide the geographic longitude, latitude, and height above sea level for the origin of the site. The origin of the site is the local placement.
The provision of longitude, latitude, height at the IfcSite for georeferencing is provided for upward compatibility reasons. It requires a single instance of IfcSite and WGS84 as coordinate reference system.
For exact georeferencing (or referencing to any other geographic coordinate system other than WSG84) the entities IfcCoordinateReferenceSystem and IfcMapConversion have to be used to define an exact mapping of the project engineering coordinate system to the geographic (or map) coordinate system.
- reference height of site is provided by: IfcSite.RefElevation, it is given according to the height datum used at this location.
- the reference height of each building situated at the site is given against the same height datum used at this location.
- the elevations of each storey belonging to each building are given as local height relative to the reference height of the building.

5.4.3.63.2 Entity inheritance
5.4.3.63.3 Attributes
# | Attribute | Type | Description |
---|---|---|---|
IfcRoot (4) | |||
IfcObjectDefinition (7) | |||
IfcObject (5) | |||
IfcProduct (5) | |||
IfcSpatialElement (6) | |||
IfcSpatialStructureElement (1) | |||
Click to show 28 hidden inherited attributes Click to hide 28 inherited attributes | |||
IfcSite (5) | |||
10 | RefLatitude | OPTIONAL IfcCompoundPlaneAngleMeasure |
World Latitude at reference point (most likely defined in legal description). Defined as integer values for degrees, minutes, seconds, and, optionally, millionths of seconds with respect to the world geodetic system WGS84. |
11 | RefLongitude | OPTIONAL IfcCompoundPlaneAngleMeasure |
World Longitude at reference point (most likely defined in legal description). Defined as integer values for degrees, minutes, seconds, and, optionally, millionths of seconds with respect to the world geodetic system WGS84. |
12 | RefElevation | OPTIONAL IfcLengthMeasure |
Datum elevation relative to sea level. |
13 | LandTitleNumber | OPTIONAL IfcLabel |
The land title number (designation of the site within a regional system). |
14 | SiteAddress | OPTIONAL IfcPostalAddress |
Address given to the site for postal purposes. |
5.4.3.63.4 Property sets
-
Pset_Address
- Purpose
- Description
- UserDefinedPurpose
- InternalLocation
- AddressLines
- PostalBox
- Town
- Region
- PostalCode
- Country
- TelephoneNumbers
- FacsimileNumbers
- PagerNumber
- ElectronicMailAddresses
- WWWHomePageURL
- MessagingIDs
-
Pset_AirSideSystemInformation
- Description
- AirSideSystemType
- AirSideSystemDistributionType
- TotalAirFlow
- EnergyGainTotal
- AirFlowSensible
- EnergyGainSensible
- EnergyLoss
- InfiltrationDiversitySummer
- InfiltrationDiversityWinter
- ApplianceDiversity
- HeatingTemperatureDelta
- CoolingTemperatureDelta
- Ventilation
- FanPower
-
Pset_LandRegistration
- LandID
- IsPermanentID
- LandTitleID
-
Pset_PropertyAgreement
- AgreementType
- TrackingIdentifier
- AgreementVersion
- AgreementDate
- PropertyName
- CommencementDate
- TerminationDate
- Duration
- Options
- ConditionCommencement
- Restrictions
- ConditionTermination
-
Pset_Risk
- RiskName
- RiskType
- NatureOfRisk
- RiskAssessmentMethodology
- UnmitigatedRiskLikelihood
- UnmitigatedRiskConsequence
- UnmitigatedRiskSignificance
- MitigationPlanned
- MitigatedRiskLikelihood
- MitigatedRiskConsequence
- MitigatedRiskSignificance
- MitigationProposed
- AssociatedProduct
- AssociatedActivity
- AssociatedLocation
-
Pset_SiteCommon
- Reference
- BuildableArea
- SiteCoverageRatio
- FloorAreaRatio
- BuildingHeightLimit
- TotalArea
-
Pset_SiteWeather
- MaxAmbientTemp
- MinAmbientTemp
-
Pset_SpaceAirHandlingDimensioning
- CoolingDesignAirFlow
- HeatingDesignAirFlow
- SensibleHeatGain
- TotalHeatGain
- TotalHeatLoss
- CoolingDryBulb
- CoolingRelativeHumidity
- HeatingDryBulb
- HeatingRelativeHumidity
- VentilationDesignAirFlow
- DesignAirFlow
- CeilingRAPlenum
- BoundaryAreaHeatLoss
-
Pset_SpaceCommon
- Reference
- IsExternal
- GrossPlannedArea
- NetPlannedArea
- PubliclyAccessible
- HandicapAccessible
-
Pset_SpaceCoveringRequirements
- FloorCovering
- FloorCoveringThickness
- WallCovering
- WallCoveringThickness
- CeilingCovering
- CeilingCoveringThickness
- SkirtingBoard
- SkirtingBoardHeight
- Molding
- MoldingHeight
- ConcealedFlooring
- ConcealedFlooringOffset
- ConcealedCeiling
- ConcealedCeilingOffset
-
Pset_SpaceFireSafetyRequirements
- FireRiskFactor
- FlammableStorage
- FireExit
- SprinklerProtection
- SprinklerProtectionAutomatic
- AirPressurization
-
Pset_SpaceHVACDesign
- TemperatureSetPoint
- TemperatureMax
- TemperatureMin
- TemperatureSummerMax
- TemperatureSummerMin
- TemperatureWinterMax
- TemperatureWinterMin
- HumiditySetPoint
- HumidityMax
- HumidityMin
- HumiditySummer
- HumidityWinter
- DiscontinuedHeating
- NaturalVentilation
- NaturalVentilationRate
- MechanicalVentilation
- MechanicalVentilationRate
- AirConditioning
- AirConditioningCentral
- AirHandlingName
-
Pset_SpaceLightingDesign
- ArtificialLighting
- Illuminance
-
Pset_SpaceOccupancyRequirements
- OccupancyType
- OccupancyNumber
- OccupancyNumberPeak
- OccupancyTimePerDay
- AreaPerOccupant
- MinimumHeadroom
- IsOutlookDesirable
-
Pset_SpaceThermalLoad
- People
- Lighting
- EquipmentSensible
- VentilationIndoorAir
- VentilationOutdoorAir
- RecirculatedAir
- ExhaustAir
- AirExchangeRate
- DryBulbTemperature
- RelativeHumidity
- InfiltrationSensible
- TotalSensibleLoad
- TotalLatentLoad
- TotalRadiantLoad
-
Pset_SpaceThermalLoadPHistory
- PeopleHistory
- LightingHistory
- EquipmentSensibleHistory
- VentilationIndoorAirHistory
- VentilationOutdoorAirHistory
- RecirculatedAirHistory
- ExhaustAirHistory
- AirExchangeRateTimeHistory
- DryBulbTemperatureHistory
- RelativeHumidityHistory
- InfiltrationSensibleHistory
- TotalSensibleLoadHistory
- TotalLatentLoadHistory
- TotalRadiantLoadHistory
-
Pset_SpaceThermalPHistory
- CoolingAirFlowRate
- HeatingAirFlowRate
- VentilationAirFlowRateHistory
- ExhaustAirFlowRate
- SpaceTemperatureHistory
- SpaceRelativeHumidity
-
Pset_ThermalLoad
- OccupancyDiversity
- LightingDiversity
- ApplianceDiversity
- OutsideAirPerPerson
- ReceptacleLoadIntensity
- AppliancePercentLoadToRadiant
- LightingLoadIntensity
- LightingPercentLoadToReturnAir
- TotalCoolingLoad
- TotalHeatingLoad
- InfiltrationDiversitySummer
- InfiltrationDiversityWinter
- LoadSafetyFactor
-
Pset_Tolerance
- ToleranceDescription
- ToleranceBasis
- OverallTolerance
- HorizontalTolerance
- OrthogonalTolerance
- VerticalTolerance
- PlanarFlatness
- HorizontalFlatness
- ElevationalFlatness
- SideFlatness
- OverallOrthogonality
- HorizontalOrthogonality
- OrthogonalOrthogonality
- VerticalOrthogonality
- OverallStraightness
- HorizontalStraightness
- OrthogonalStraightness
- VerticalStraightness
-
Pset_Uncertainty
- UncertaintyBasis
- UncertaintyDescription
- HorizontalUncertainty
- LinearUncertainty
- OrthogonalUncertainty
- VerticalUncertainty
-
Qto_BodyGeometryValidation
- GrossSurfaceArea
- NetSurfaceArea
- GrossVolume
- NetVolume
- SurfaceGenusBeforeFeatures
- SurfaceGenusAfterFeatures
-
Qto_SiteBaseQuantities
- GrossPerimeter
- GrossArea
5.4.3.63.5 Concept usage
Concept | Usage | Description | |
---|---|---|---|
IfcRoot (2) | |||
IfcObjectDefinition (9) | |||
IfcObject (5) | |||
IfcProduct (18) | |||
IfcSpatialElement (11) | |||
IfcSpatialStructureElement (2) | |||
Click to show 47 hidden inherited concepts Click to hide 47 inherited concepts | |||
IfcSite (9) | |||
Body Geometry | General |
The body representation of IfcSite may be typically defined using a solid or surface model. Applicable solids are Breps and Tessellations. Applicable surface models are the IfcFaceBasedSurfaceModel and the IfcShellBasedSurfaceModel. The representation identifier and type of this representation of IfcSite is:
|
|
FootPrint GeomSet Geometry | General |
The foot print representation of IfcSite is given by either a single 2D curve (such as IfcPolyline or IfcCompositeCurve), or by a list of 2D curves (in case of inner boundaries). |
|
Product Local Placement | General |
The local placement for IfcSite is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations.
|
|
Property Sets for Objects | General |
This concept can be applied to the following resources: |
|
Quantity Sets | General |
This concept can be applied to the following resources: |
|
Site Attributes | General |
No description available. |
|
Spatial Composition | General |
By using the inverse relationship IfcSite.Decomposes it references IfcProject || IfcSite through IfcRelAggregates.RelatingObject, If it refers to another instance of IfcSite, the referenced IfcSite needs to have a different and higher CompositionType, i.e. COMPLEX (if the other IfcSite has ELEMENT), or ELEMENT (if the other IfcSite has PARTIAL). This concept can be applied to the following resources: |
|
Spatial Container | General |
If there are building elements and/or other elements directly related to the IfcSite (like a fence, or a shear wall), they are associated with the IfcSite by using the objectified relationship IfcRelContainedInSpatialStructure. The IfcSite references them by its inverse relationship:
|
|
Spatial Decomposition | General |
By using the inverse relationship IfcSite.IsDecomposedBy it references (IfcSite || IfcBuilding || IfcSpace by IfcRelAggregates.RelatedObjects). If it refers to another instance of IfcSite, the referenced IfcSite needs to have a different and lower CompositionType, i.e. ELEMENT (if the other IfcSite has COMPLEX), or PARTIAL (if the other IfcSite has ELEMENT). This concept can be applied to the following resources: |
5.4.3.63.6 Examples
-
Figure 5.4.3.63.C -
Figure 5.4.3.63.D -
Figure 5.4.3.63.E -
Figure 5.4.3.63.F -
Figure 5.4.3.63.G -
Figure 5.4.3.63.H -
Figure 5.4.3.63.I -
Figure 5.4.3.63.J -
Figure 5.4.3.63.K -
Figure 5.4.3.63.L
5.4.3.63.7 Formal representation
ENTITY IfcSite SUBTYPE OF (IfcSpatialStructureElement); RefLatitude : OPTIONAL IfcCompoundPlaneAngleMeasure; RefLongitude : OPTIONAL IfcCompoundPlaneAngleMeasure; RefElevation : OPTIONAL IfcLengthMeasure; LandTitleNumber : OPTIONAL IfcLabel; SiteAddress : OPTIONAL IfcPostalAddress; END_ENTITY;