Documentation: Definition: A quantity specifying a point on the axis of natural time. A point in time is most often represented as a calendar expression. Semantically, however, time is independent from calendars and best described by its relationship to elapsed time (measured as a physical quantity in the dimension of time.) A point in time plus an elapsed time yields another point in time. Inversely, a point in time minus another point in time yields an elapsed time. As nobody knows when time began, a point in time is conceptualized as the amount of time that has elapsed from some arbitrary zero-point, called an epoch. Because there is no absolute zero-point on the time axis natural time is a difference-scale quantity, where only differences are defined but no ratios. (For example, no point in time is — absolutely speaking — "twice as late" as another point in time.) Given some arbitrary zero-point, one can express any point in time as an elapsed time measured from that offset. Such an arbitrary zero-point is called an epoch. This epoch-offset form is used as a semantic representation here, without implying that any system would have to implement the TS data type in that way. Systems that do not need to compute distances between points in time will not need any other representation than a calendar expression literal. Exhibit 173: type PointInTime alias TS specializes QTY { PQ offset; CS calendar; INT precision; PQ timezone; BL equal(ANY x); literal ST; };

Superclasses

• Quantity

Subclasses

• RelativePointInTime

Types

• HL7_Data_Type

Template Slots
	Slot Name	Documentation	Type	Cardinality
	calender	A code specifying the calendar used in the literal representation of this point in time	Class	0:1
	label	A short human readable string indicating the content of the instancehuman-readable string for the instance	String	0:1
	literal	A literal representation of the data. For example, "2003-02-23" is a literal representation of a time point.	String	0:1
	nullFlavor	If a value is an exceptional value (NULL-value), this specifies in what way and why proper information is missing.	Class	0:1
	offset	The elapsed time since any constant epoch, measured as a physical quantity in the dimension of time (i.e., comparable to one second.)	PhysicalQuantity	0:1
	time_zone	The difference between the local time in that time zone and Universal Coordinated Time (UTC, formerly called Greenwich Mean Time, GMT). The time zone is a physical quantity in the dimension of time (i.e., comparable to one second.) A zero time zone value specifies UTC. The time zone value does not permit conclusions about the geographical longitude or a conventional time zone name.	PhysicalQuantity	0:1

Own Slots
	Slot Name	Value
	alias	TS
	semantic_properties	PQ offset; CS calendar; INT precision; PQ timezone; BL equal(ANY x);
	:ROLE	Concrete
	:SLOT-CONSTRAINTS

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