Here are the recommendations of the Date subgroup. This is _not_ for
the "Finnish finish", which will likely be simpler and shorter.
-John
==================================
Date Ranges and DC.Date Subelement Definitions
27 January 1998
Date Ranges
===========
It is proposed that Date ranges be specified using a subset of the ISO 8601
"period of time" specification as restricted to dates conformant with the
W3C technical note specification (http://www.w3.org/TR/NOTE-datetime).
A typical range is given as start and end dates separated by a '/' (slash)
character. Either the start or end date may be missing. Examples include
1992/1997 # starts in 1992 and ends in 1997
1998-01-05T08:15/1998-01-05T13:15 # a range of 5 hours in early 1998
1948/ # from 1948 (no end specified)
/1989 # until 1989 (no start specified)
DC.Date Subelements
===================
Used without a subelement designation (i.e., unqualified), a DC.Date
element contains a date associated with the creation or availability
of the resource. All DC.Date subelements are consistent with this
definition, but allow increased precision. They are intended for those
collections (e.g., libraries and archives) and searchers for whom the
benefit to discovery may justify the extra cost in metadata creation
and maintenance.
These subelements may be seen as falling into the three groups below,
with DC.Created and DC.Issued providing perhaps the most commonly
required extra precision.
Resource Origination Resource Release Resource Transfer
-------------------- ---------------- -----------------
DC.Date.Created DC.Date.Issued DC.Date.Accepted
DC.Date.DataGathered DC.Date.Available DC.Date.Acquired
DC.Date.Valid
1. DC.Date.Created
------------------
Date of creation of the resource.
When DC.Date is insufficiently precise, use this subelement to distinguish
a date that identifies just the creation of the present resource. Examples
include the date that an article was written, a photograph taken, a piece
of music composed, or a performance recorded. An HTML file created in 1997
as a transcription of an article written in 1875 could have both
DC.Date.Created: 1997
DC.Source.Date.Created: 1875
Alternatively, a simpler description could include exactly one date as either
DC.Date: 1997
or, depending on the metadata provider's preference,
DC.Date: 1875
If you wished to describe different versions of a resource with one resource
description, it would be appropriate to put the creation date of the latest
version in DC.Date.Created. On the other hand, you might instead choose
to describe each version with a separate resource description.
2. DC.Date.Issued
-----------------
Date of formal issuance (e.g., publication) of the resource.
When DC.Date is insufficiently precise, use this subelement to distinguish
a release date that has recognized legal (e.g., copyright) or institutional
(e.g., posting of a staff policy change) significance. For example, the
description of a work published posthumously might have just "DC.Date: 1997",
just "DC.Date: 1948", or both
DC.Date.Issued: 1997
DC.Date.Created: 1948
A government file, officially released in 1997, consisting of photographs
taken in 1985 of hundreds of meteorite fragments collected in 1952 could
be described with the following metadata:
DC.Date.Issued: 1997
DC.Date.Created: 1985
DC.Date.DataGathered: 1952
3. DC.Date.Accepted
-------------------
Date of acceptance (e.g., dissertation or treaty) of the resource.
When DC.Date and DC.Date.Issued are insufficiently precise, use this
subelement to indicate when the resource was formally adopted by a
party that accepts or vouches for it.
4. DC.Date.Available
--------------------
Date (often a range) that the resource will become or did become available.
When DC.Date and DC.Date.Issued are insufficiently precise, use this
subelement to indicate a start, end, or both start and end of a period
during which access to the resource was or will be granted. It may be
needed to indicate an availability period that will start or end in the
future, or did come to an end in the past. For example, a journal
collection ranging from 1955 to 1996 may be given as
DC.Date.Available: 1955/1996
5. DC.Date.Acquired
-------------------
Date of acquistion or accession.
When DC.Date and DC.Date.Issued are insufficiently precise, use this
subelement to distinguish the time that a resource was acquired or
accessioned in the context of a collection to which it belongs or
in which it resides. For example,
DC.Title: Treaty of 1645
DC.Date.Issued: 1645
DC.Date.Accepted: 1646
DC.Date.Acquired: 1958
6. DC.Date.DataGathered
-----------------------
Date of sampling of the information in the resource.
When DC.Date and DC.Date.Created are insufficiently precise, use this
subelement to distinguish the time of raw data creation as opposed to
resource content (e.g., intellectual content) creation, which belongs
in DC.Date.Created. Examples include the date that a group of weather
stations were sampled and a range of times during which radiation
measurements were taken. To identify the date when a photograph was
taken, DC.Date.Created is recommended.
7. DC.Date.Valid
----------------
Date (often a range) of validity of the resource.
When DC.Date and DC.Date.Issued are insufficiently precise, use this
subelement to indicate when the resource content may be considered to hold
true. In a somewhat labored example, suppose a public transit system is in
the practice of creating a new bus schedule, allowing two weeks for issuance
of a print run, allowing two more weeks for printed copies of the schedule
to be placed in distribution racks, and finally being required to do so at
least one month in advance of drivers switching the timing on their routes.
Metadata for such a bus schedule might include all of the following elements:
DC.Description: City Bus Schedule
DC.Date.Created: 1997-11-01
DC.Date.Issued: 1997-11-15
DC.Date.Available: 1997-12-01/1998-06-01
DC.Date.Valid: 1998-01-01/1998-06-01
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