Description of temporal extent structured with separate values for the various elements of a calendar-clock system.

Generalized duration description

Description of temporal extent structured with separate values for the various elements of a calendar-clock system.

The extent of a time duration expressed as a GeneralDurationDescription depends on the Temporal Reference System. In some calendars the length of the week or month is not constant within the year. Therefore, a value like "2.5 months" may not necessarily be exactly compared with a similar duration expressed in terms of weeks or days. When non-earth-based calendars are considered even more care must be taken in comparing durations.