Date realizationEpoch[0..1], in Class CD_Datum

Documentation
The time after which this datum definition is valid. This time may be precise (e.g. 1997.0 for IRTF97) or merely a year (e.g. 1986 for NAD83(86)). In the latter case, the epoch usually refers to the year in which a major recalculation of the geodetic control network, underlying the datum, was executed or initiated. An old datum may remain valid after a new datum is defined. Alternatively, a datum may be replaced by a later datum, in which case the realization epoch for the new datum defines the upper limit for the validity of the replaced datum.

Export ControlPublicAccessContainmentUnspecified
StaticNoDerivedNo