About Geographic Information Systems (GIS)

The IfcSite entity provides the georeferencing data (longitude, latitude and height above sea level) for the origin of the site. It also acts as a spatial container for all other entities directly related to the site, such as buildings, building stories and building elements. The origin of the site is the local placement root of all the entities contained in the site.

This page discusses:

Note: To support georeferencing, there must be exactly one IfcSite in the project.

The current section describes IfcSite entities. More information about the support of entities is given in the following sections.

Coordinate Reference System (CRS)

Following entites are supported at import and export.

IFC Entity Description Comment
IfcMapConversion Transforms the local engineering coordinate system into the coordinate reference system of the underlying map. Created with the name of the used CRS and values of Eastings, Northings and Orthogonal Height.
Note: Attributes XAxisAbscissa, XAxisOrdinate and Scale are not supported.
IfcProjectedCRS Coordinate reference system of the map to which the map translation of the local engineering coordinate system relates. Created with the name of the used CRS and values of Eastings, Northings and Orthogonal Height.

Site Attributes

IFC EntityDescriptionComment
IfcSite.Description User-assigned description. Optional attribute
IfcSite.LongName Use-assigned name (long name). Optional attribute
IfcSite.Name User-assigned unique number or key of the site (short name). Optional attribute

Site Georeferencing Attributes ()

Always uses WGS84 CRS

IFC EntityDescriptionComment
IfcProject.RepresentationContexts.IfcGeometricRepresentationContext.TrueNorth Orientation of site coordinate system relative to True North Optional attribute.

Always assumed to be (0.,1.) in 3DEXPERIENCE
IfcSite.Latitude Geographic latitude in geodetic system WGS84, e.g. Chicago Harbor Light 41.53.30 ("+" = N) Optional attribute in IFC 4 when IfcMapConversion is provided
IfcSite.Longitude Geographic longitude in geodetic system WGS84, e.g. Chicago Harbor Light -87.35.40 ("-" = W) Optional attribute in IFC 4 when IfcMapConversion is provided
IfcSite.RefElevation Elevation above the height datum -

Site Address

Address given to the site for postal purposes

IFC EntityDescriptionComment
IfcSite.SiteAddress.AddressLines Depends on local usage, street number, street name. Optional attribute
IfcSite.SiteAddress.PostalCode Code used by the postal service -
IfcSite.SiteAddress.Region Name of a region or state -
IfcSite.SiteAddress.Town Name of a town or city -