innovation in metadata design, implementation & best practices
Title: Problems with the definition of dc:date
See also: http://dublincore.org/usage/meetings/2004/10/ISSUES/
Agenda frozen: 2004-10-02 07:25, Saturday
Maintainer: Tom Baker
Note: If any of the links below are broken, please refer to
the meeting packet
for copies of the key documents discussed at the meeting.
Andy stated the problem on 2004-07-27 on the DC-USAGE list:
This issue has popped up twice on the lists recently.
dc:date is defined as
A date of an event in the lifecycle of the resource.
which superficially looks like the intention was a single
date rather than a date range.
But I tend to agree with what Charles says here.
Any single date is really a shorthand for a time-range
(00.00 to 23.59 on the given day)... so what I suspect
we really meant by dc:date was
A date/time (or date/time range) of an event in the lifecycle of the
Would it be worth trying to clarify this in our
documentation? Or do people disagree with my analysis
---------- Forwarded message ----------
Date: Mon, 26 Jul 2004 21:23:23 -0400 (EDT)
From: Charles McCathieNevile <firstname.lastname@example.org>
Subject: Re: Dublin Core 'available' date range
Resent-Date: Mon, 26 Jul 2004 21:24:06 -0400 (EDT)
You could model its availability as an event with a start and end time using
the RDF/iCal work - http://www.w3.org/2002/12/cal/
Although it is hard to say if this is the same as what dublin core thinks a
single date might be. If it doesn't, it probably should. Time being a
continuum (at least as far as we measure it) any date or time represents a
(I was involved in one of the discussions Andy mentioned above )
I was sort of willing to be persuaded by Charles McC-N's message to rdf-
interest too. i.e. a date is always really a reference to a period of time.
But.... ISO8601:2000 does make a distinction between
(a) a date, defined as
identification of a particular calendar day, expressed by some combination
of the data elements calendar year, calendar month, calendar week, calendar
day or day of the year
(b) a time interval or period of time, defined as
portion of time between two time points
I was kind of surprised to read that a date is always a reference to a
_day_ but that's what it says.... (it may be of reduced precision)
If the intention is that a value of dc:date can be either a date, a
combination of date and time, or a time interval/period of time -
especially as DCMI has accepted ISO8601 as an encoding scheme - I think the
terminology in DC definition probably should be consistent with ISO8601
usage, and there's a case for amending the definition of dc:date.
FWIW, I think that would still leave open the possibility that some
refinements of dc:date could specify that their values are specifically
dates (and not time intervals), if that was required.
Incidentally, I notice that ISO8601 also supports the representation of
time of day alone. But I'm assuming a time that is not associated with a
date is not an acceptable value for dc:date? I'm not sure whether that
merits some qualifying note in the (forthcoming!) description of ISO8601 as
an encoding scheme.
You can get a final(?) draft of ISO8601:2000 at . But I guess you have
to buy the approved version.