Re: Encoding an incomplete date as xsd:dateTime

I've been thinking about date representations a lot lately.  Even if
you're going to cobble something together out of the various XSD
types,  it still helps to have a theory.

A better underlying data type for dates is a time interval or set of
time intervals.

This represents the fact that many "events" happen over a time
interval (such as a meeting or movie show time),  that we often only
know a year or a day,  that things are measured on idiosyncratic time
basis such as the fiscal years of various organizations,  that there
are both practical and theoretical limits on both the precision and
accuracy of time measurements.

Intervals have their charms,  but if you include interval sets you can
also represent concepts such as "Monday", "June 25" and "the third
Tuesday of the month".

Of course,  it creates trouble that there is no total ordering over
intervals/interval sets,  but that's a fundamental problem to any
flexible time representation.
ᐧ

On Mon, Feb 10, 2014 at 9:37 AM, Heiko Paulheim
<heiko@informatik.uni-mannheim.de> wrote:
> Hi all,
>
> xsd:dateTime and xsd:date are used frequently for encoding dates in RDF,
> e.g., for birthdays in the vcard ontology [1]. Is there any best practice to
> encode incomplete date information, e.g., if only the birth *year* of a
> person is known?
>
> As far as I can see, the XSD spec enforces the provision of all date
> components [2], but "1997-01-01" seems like a semantically wrong way of
> expressing that someone is born in 1997, but the author does not know
> exactly when.
>
> Thanks,
> Heiko
>
> [1] http://www.w3.org/2006/vcard/ns
> [2] http://www.w3.org/TR/xmlschema-2/#dateTime
> [3] http://www.w3.org/TR/xmlschema-2/#date
>
> --
> Dr. Heiko Paulheim
> Research Group Data and Web Science
> University of Mannheim
> Phone: +49 621 181 2646
> B6, 26, Room C1.08
> D-68159 Mannheim
>
> Mail: heiko@informatik.uni-mannheim.de
> Web: www.heikopaulheim.com
>
>



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Paul Houle
Expert on Freebase, DBpedia, Hadoop and RDF
(607) 539 6254    paul.houle on Skype   ontology2@gmail.com

Received on Wednesday, 25 June 2014 14:00:46 UTC