API Reference > imodeljs-common > Geometry > HorizontalCRS > datum datum Readonly datum: undefined | GeodeticDatum The complete definition of the geodetic datum referred to by datumId. It can also be used if the datum is not stored in either service or dictionary. Defined in core/common/src/geometry/CoordinateReferenceSystem.ts Line 167 Last Updated: 11 June, 2024