Returns a feature containing the union of the geometry of a feature. This leaves single geometries untouched, and unions multi geometries.
The feature the geometry of which is being unioned.
|ErrorMargin, default: null|
The maximum amount of error tolerated when performing any necessary reprojection.
|Projection, default: null|
If specified, the union will be performed in this projection. Otherwise it will be performed in a spherical coordinate system.