API Reference > imodeljs-common > Geometry > HorizontalCRS > ellipsoidId ellipsoidId Readonly ellipsoidId: undefined | string The identifier of the geodetic ellipsoid as stored in the dictionary or the service database. This property is exclusive of having datumId and datum properties undefined. Defined in core/common/src/geometry/CoordinateReferenceSystem.ts Line 172 Last Updated: 12 June, 2024