Time Intervals
A time interval is the intervening time between two time points. The amount of intervening time is expressed by a duration (as described in the previous section). The two time points (start and end) are expressed by either a combined date and time representation or just a date representation.
There are four ways to express a time interval:
- Start and end, such as "2007-03-01T13:00:00Z/2008-05-11T15:30:00Z"
- Start and duration, such as "2007-03-01T13:00:00Z/P1Y2M10DT2H30M"
- Duration and end, such as "P1Y2M10DT2H30M/2008-05-11T15:30:00Z"
- Duration only, such as "P1Y2M10DT2H30M", with additional context information
Of these, the first three require two values separated by an interval designator which is usually a solidus or forward slash "/". Clause 4.4.2 of the standard notes that: "In certain application areas a double hyphen is used as a separator instead of a solidus." The standard does not define the term "double hyphen", but previous versions used notations like "2000--2002". Use of a double hyphen instead of a solidus allows inclusion in computer filenames. A solidus is a reserved character and not allowed in a filename in common operating systems.
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If greater precision is desirable to represent the time interval, then more time elements can be added to the representation. An observation period that has a duration of approximately three days, for example, can be succinctly shown as "2007-11-13/15", i.e. from any time on 2007-11-13 to any time on 2007-11-15. If a more exact start and end of the observation period need to be shown either for clarity or for measurement and recording purposes, the same time interval representation could be expanded to "2007-11-13T00:00/15T24:00", i.e. midnight at the start (T00:00) of 2007-11-13 to midnight at the end (T24:00) of 2007-11-15, a total of 72 hours.
Read more about this topic: ISO 8601
Famous quotes containing the words time and/or intervals:
“We see past time in a telescope and present time in a microscope. Hence the apparent enormities of the present.”
—Victor Hugo (18021885)
“What is most striking in the Maine wilderness is the continuousness of the forest, with fewer open intervals or glades than you had imagined. Except the few burnt lands, the narrow intervals on the rivers, the bare tops of the high mountains, and the lakes and streams, the forest is uninterrupted.”
—Henry David Thoreau (18171862)