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Re: units and durations

From: Toby A Inkster <tai@g5n.co.uk>
Date: Wed, 10 Dec 2008 14:43:58 +0000
Message-Id: <A26268F0-5FD2-46BF-B30C-7B6F22BFD7C7@g5n.co.uk>
Cc: <dbpedia-discussion@lists.sourceforge.net>, <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
To: georgi.kobilarov@gmx.de

Georgi Kobilarov wrote:

> 1. lengths:
> metre, kilometre, centimetre, km^2, etc.
> dbpedia:Rhine <http://dbpedia.org/ontology/length>
> "1320"^^<http://dbpedia.org/ontology/kilometre>


> 2. runtimes
> seconds, minutes, hours, days...
> dbpedia:Yellow_Submarine_(song) <http://dbpedia.org/ontology/runtime>
> "2:38"^^<http://dbpedia.org/ontology/minute>
> dbpedia:The_Departed <http://dbpedia.org/ontology/runtime>
> "151"^^<http://dbpedia.org/ontology/minute>
> 3. durations
> dbpedia:Thirty_Years'_War <http://dbpedia.org/ontology/date>
> "1618-1648"^^???

In terms of ISO 8601, "durations" are defined as abstract floating  
lengths of time, such as "three and a half minutes". When you fix the  
duration to a particular time, such as "three and a half minutes,  
starting now", then it is classed as an "interval".

For durations, there is there is xsd:duration. e.g.

	    "PT2M38S"^^xsd:duration .

For intervals, XSD doesn't offer a datatype, but ISO 8601 at least  
offers a machine readable standard syntax for them - intervals are  
written, slash-separated, as a start-time/end-time pair, a start-time/ 
duration pair, or a duration/end-time pair. Personally, I tend to  
represent this in RDF as:

	    "1618/1648"^^<urn:iso:std:iso:8601#timeInterval> .

Toby A Inkster
Received on Wednesday, 10 December 2008 14:44:37 UTC

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