SKOS concepts in VOTable (strawman proposal text for Sect 3.5)

[Dave Morris]

On 06/05/2012 11:30 PM, Norman Gray wrote:


>     doc: the URI is dereferenceable and provides documentation about the resource <X#f> ....
>     type: the element containing this LINK element has a 'type-like' relationship to the ....

Having two different ways of describing which element the contents of the link applies to is confusing.

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>  doc: the URI is dereferenceable and provides documentation about the resource <X#f>, where 'X' is the URI of the VOTable, and 'f' is the ID of the first containing element which has an ID attribute (that is, the attribute ancestor::*/@id[1], in XPath terms).  The URI <X#f> will also act as the Retrieval URI for the purposes of calculating a Base URI, in the sense of RFC 3986 Section 5.1.  The URI may provide human- or machine-readable representations or both, depending on the retrieval mechanism (for example a URI might provide text/html content if it is retrieved through an HTTP URI with suitable Accept headers).

The description for 'doc' refers to two different URIs as 'the URI' which means it is not clear which URI the last sentence is referring to, the URI <X#f> or the @href URI.

I'm probably reading it wrong, but in this example

    <table id='xxx'>
        <field .... >
            <link content-role='doc' href='http://www.example.org/document-001'/>
        </field>
    </table>

then because the table element has an @id attribute and the field element doesn't, does the document pointed to by the link @href provide documentation about the table, not the field ? 

Perhaps an examples might make it clearer ?

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> type: the element containing this LINK element has a 'type-like' relationship to the resource named in the href attribute.  If the href attribute names a SKOS Concept, for example, the containing element represents something which could be labelled by that Concept.  This relationship requires a rather heuristic interpretation, by design; if more precise documentation is required, then this can be provided through a link with content-role='doc'.  The URI may or might not be dereferenceable; if it is dereferenceable, it provides information about the URI itself, rather than the LINK element.

Again, perhaps some examples might make this clearer.

How about :

If content-role is 'type', then the link @href URI is a name for a type-like concept which applies to the element containing the <link> element.

In the following example, the URI 'dc:creator' is a name for a semantic type that applies to the enclosing <field> element.

    <field .... >
        <link content-role='type' href='dc:creator'/>
    </field>

If the link @href is dereferenceable, then it provides information about the type the @href is naming, rather than the element containing the link.

In the following example, the URI 'http://purl.org/dc/elements/1.1/creator' resolves to resource that describes the semantic type that applies to the enclosing <field> element, not the <field> element itself.

    <field .... >
        <link content-role='type'href='http://purl.org/dc/elements/1.1/creator'/>
    </field>

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Hope this helps,
Dave