[tdwg-content] If you need something for referring to a population, then it is probably best to do it as a related class

Mikel Egaña Aranguren megana at fi.upm.es
Mon May 9 10:24:25 CEST 2011


a little aside

On az., 2011.eko mairen 04a 04:34, Hilmar Lapp wrote:
> On May 3, 2011, at 9:00 PM, Steve Baskauf wrote:
>> But I was under the impression that one models things by describing 
>> classes and the properties that connect them.
> In OWL, properties connect instances, not classes. RDF allows 
> metaclasses (things that are classes and instances), but doing this 
> will throw most (all?) reasoners off the track.

Just to add to the discussion, puning can be used to model clases as 
instances. In fact, a common pattern I'm seing and I'm using is to use 
puning and have a class hierarchy, each class having an instance with 
the same URI, so one can refer to each class as a class or as an 
instance, depending on the context.



>>   Classes are (to me) a very different thing than instances of 
>> classes.  A model containing more than 13.6 million classes is at 
>> least 1.9 million times as complicated as a model with 7 classes.
> Yes and no. I can model a taxonomy as a subclass hierarchy of classes, 
> or as a property-based (memberOf or some such) hierarchy of 
> individuals that all instantiate a single "Taxon" class. The former 
> isn't 1 million times more complex than the latter. However, they are 
> not identical either, and which approach one chooses has significant 
> consequences for how easy it is to express things about those taxa, 
> and for inferring new things from those with a DL reasoner.
>>   I would hate to have to draw an RDF graph of that model
> I would as much hate to have to draw an RDF graph of 1.7 million 
> instances. The point being, in order to draw a graph of how someone 
> models a domain you don't draw a graph of the entire RDF triple store.
> -hilmar
> -- 
> ===========================================================
> : Hilmar Lapp  -:- Durham, NC -:- informatics.nescent.org :
> ===========================================================
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Mikel Egaña Aranguren, PhD

Marie Curie post-doc at Ontology Engineering Group, UPM

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