On 10 Dec 2008, at 15:43, Toby A Inkster wrote:
Georgi Kobilarov wrote:
1. lengths:
metre, kilometre, centimetre, km^2, etc.
dbpedia:Rhine <http://dbpedia.org/ontology/length>
"1320"^^<http://dbpedia.org/ontology/kilometre>
See:
http://idi.fundacionctic.org/muo/muo-vocab.html
Very thorough work but it makes the mistakes described here
http://esw.w3.org/topic/InterpretationProperties
So for example his example
http://forge.morfeo-project.org/wiki_en/index.php/Units_of_measurement_ontology
:Spain :area [ muo:numericalValue "504782"^^xsd:double ;
muo:measuredIn :Sq_Km ] .
will when merged with the following which represents the same area
:Spain :area [ muo:numericalValue "504782000000"^^xsd:double ;
muo:measuredIn :Sq_m ] .
give the useless
:Spain :area [ muo:numericalValue "504782"^^xsd:double ;
muo:numericalValue "504782000000"^^xsd:double ;
muo:measuredIn :Sq_m;
muo:measuredIn :Sq_Km ] .
if the :area relation is considered to be functional, which it should
very well be considered to be.
A better solution is found here:
http://www.w3.org/2007/ont/unit
Use cwm to read it
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.
dbpedia:Yellow_Submarine_(song)
ont:runtime
"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:
dbpedia:Thirty_Years'_War
ont:date
"1618/1648"^^<urn:iso:std:iso:8601#timeInterval> .
There are temporal ontologies that would work better here. Think of
time slices.
http://www.w3.org/TR/owl-time/
--
Toby A Inkster
<mailto:[EMAIL PROTECTED]>
<http://tobyinkster.co.uk>
