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Re: xsd:date in DCAT

From: Stasinos Konstantopoulos <konstant@iit.demokritos.gr>
Date: Fri, 5 Apr 2013 10:33:58 +0300
To: Phil Archer <phila@w3.org>
Cc: GLD Public Comments <public-gld-comments@w3.org>
Message-ID: <20130405073358.GC13394@iit.demokritos.gr>
Dear Phil, GLDers,

kind reminder of some thoughts I had posted earlier, regarding ways to
compromise between current (mal)practice and accurate ways to express "I
don't know exactly when".

http://lists.w3.org/Archives/Public/public-gld-wg/2012Jan/0094.html

best,
s


On Thu Apr  4 10:16:49 2013 Phil Archer said:

> Having noted this afternoon's agenda item on ADMS I'm working on
> that document right now which is causing me to look at DCAT more
> carefully than I have of late - which is my excuse for just noticing
> something I should have seen before. I ask that the WG treats this
> as a last call comment.
> 
> In the text related to the use of dcterms:issued [1] we say:
> 
> "rdfs:Literal typed as xsd:date. The date is encoded as a literal in
> "YYYY-MM-DD" form (ISO 8601 Date and Time Formats). If the specific
> day or month are not known, then 01 should be specified."
> 
> I remember raising this at our previous f2f last year as I find it
> objectionable that we actively encourage sloppy practice and
> inaccurate data.
> 
> If I know that something was issued in March 2013 then I can write
> 
> dcterms:issued "2013-03"^^xsd:gYearMonth
> 
> That conveys exactly what I mean - that the thing was issued at some
> point between 2013-03-01T00:00:00 and 2013-03-31T23:59:59. But I
> don't know when. It is accurate, if not precise.
> 
> But DCAT says we shouldn't do this. We should render it as
> 2013-03-01 which means that the thing was issued sometime in the 24
> hour period known as 1st March. That may be wrong by as much as 30
> days and gives an entirely bogus impression of accuracy.
> 
> I suspect that the reason for this is that catalogues habitually
> don't understand xsd:gYearMonth. If that's the case then that's
> application-specific and a profile may wish to make it clear that
> dates must be xsd:date only, even if that means it will create
> inaccuracies where none exist in the original data, but IMHO this
> sloppiness should not be included in the DCAT spec. Therefore I
> suggest that the text for this property says:
> 
> "rdfs:Literal using the relevant ISO 8601 Date and Time compliant
> string and typed using the appropriate XML Schema datatype
> [[XMLSCHEMA-2]]"
> 
> 
> 
> [1] http://www.w3.org/TR/vocab-dcat/#Property:catalog_release_date
> 
> 
> 
> -- 
> 
> 
> Phil Archer
> W3C eGovernment
> http://www.w3.org/egov/
> 
> http://philarcher.org
> +44 (0)7887 767755
> @philarcher1
Received on Friday, 5 April 2013 07:29:58 UTC

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