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Re: @itemid and URL properties in schema.org

From: Jeni Tennison <jeni@jenitennison.com>
Date: Sat, 5 Nov 2011 10:18:04 +0000
Cc: public-vocabs@w3.org, HTML Data Task Force WG <public-html-data-tf@w3.org>, Gregg Kellogg <gregg@kellogg-assoc.com>
Message-Id: <6F476671-934F-4F0B-9391-AD5197FD0791@jenitennison.com>
To: Peter Mika <pmika@yahoo-inc.com>
Hi Peter,

On 4 Nov 2011, at 20:44, Peter Mika wrote:
> We will strive to keep the OWL description in sync with the microdata version.

:) That would be great, thanks.

> In general, as you know, OWL makes a distinction between datatype- and object-properties, while microdata doesn't... (but it makes the slightly different distinction between URL valued properties and non-URL valued properties.)
> So the OWL description will always be stricter (more complete in a way) than the microdata description. It captures datatypes (URL, Number etc.) as subclasses of Literal and the object/datatype-property distinction, which is probably the most faithful translation of the intent of the spec.

This is part of the point of my posting about this :) We have a problem here, in that the mapping of properties typed URL to literal values in the schema.org OWL ontology clashes with the assumption in the microdata-to-RDF mapping that we've been developing [1], which assumes that any @href, @src etc provides the identifier of a resource, giving the property an object value rather than a literal value.

Based on the examples within the schema.org documentation (where @href is used when an AudioObject is expected, for example), my feeling is that values that are typed as URL in schema.org should actually be mapped onto object properties in the OWL ontology.



[1] https://dvcs.w3.org/hg/htmldata/raw-file/2f11ba803758/microdata-rdf/index.html
Jeni Tennison
Received on Saturday, 5 November 2011 10:21:04 UTC

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