[tei-council] <when>/@absolute and dateTime values

[Lou Burnard]

On 01/01/13 03:52, Syd Bauman wrote:
> I think your analysis is pretty correct, although I reach a slightly
> different conclusion.

Twas ever thus.... just for the record, I think it might be better to 
make the example conform to the documentation, i.e. reinstate the 
"+01:00" rather than removing the reference to BST.
The comment on should make explicit that this is not required in the 
(more usual) circumstance where the times in the timeline are just 
relative to a specified <when>, which is not itself absolutely located 
in time. This is the only situation  in which one might care about the 
date, or time zone, of course.


>
> * The "BST" is leftover from P4, when it was specified in the
>    absolute=. I don't know how it got dropped. Seems to me the value
>    of absolute= in that example in TS should have been 12:20:01+01:00.
>
> * While you're right, and in many cases the note in data.temporal.w3c
>    is right, in many (if not most) cases where we can imagine
>    <timeline> being used, dates (and for that matter time zones) are
>    simply irrelevant. In many (if not most) cases, although the times
>    might be compared, they're only going to be compared to other
>    <when> in the same timeline, or other <timeline>s in the same
>    corpus. Thus requiring a date (IMHO) would be silly.
>
> So my first reaction is that think we should drop the "BST", and
> re-iterate the warning that if you expect the values in your timeline
> to be compared to other values out there in the world, you should
> include a date and timezone.
>
>> This bit of Chapter 8:
>>
>> <http://www.tei-c.org/release/doc/tei-p5-doc/en/html/TS.html#TSSAPA>
>>
>> contains this example:
>>
>> <timeline unit="s" origin="#TS-P1">
>>    <when xml:id="TS-P1" absolute="12:20:01"/>
>>    <when xml:id="TS-P2" interval="4.5" since="#TS-P1"/>
>>    <when xml:id="TS-P6"/>
>>    <when xml:id="TS-P3" interval="1.5" since="#TS-P6"/>
>> </timeline>
>>
>> with the following commentary:
>>
>> "... TS-P1 is located absolutely, at 12:20:01:01 BST. TS-P2 is 4.5
>> seconds later than TS-P2 (i.e. at 12:20:46)..."
>>
>> I was first of all puzzled by the assertion that this is BST (British
>> Summer Time). Nothing in the example suggests that there is any
>> timezone offset from UTC, which I assumed was the default. Then I
>> looked at the datatype for @absolute, which is data.temporal.w3c,
>> about which we say in a note:
>>
>> "If it is likely that the value used is to be compared with another,
>> then a time zone indicator should always be included, and only the
>> dateTime representation should be used."
>>
>> <http://www.tei-c.org/release/doc/tei-p5-doc/en/html/ref-data.temporal.w3c.html>
>>
>> So in this context, the xsd:dateTime representation should be used,
>> and it should include a timezone. So I looked at the W3C spec:
>>
>> <http://www.w3.org/TR/xmlschema-2/#dateTime>
>>
>> which, as I read it, requires the presence of a date; whereas our
>> example has only a time.
>>
>> It seems to me, therefore, that this usage of @absolute is wrong on
>> two counts: first, it should include a date, and second, it ought to
>> have a timezone offset of 'Z', the canonical representation for an
>> offset of zero, i.e. UTC. Further, I think the claim that this value
>> is BST makes no sense (BST is UTC+1) given that the example has no
>> timezone offset in it.
>>
>> Am I missing anything here?