Re: URI scheme advice for an RDF schema

Hi John,

These are very thoughtful questions, I am also struggling with the answers.

A couple of days ago I posted some observations that may be relevant to your considerations:

http://lists.w3.org/Archives/Public/public-lod/2014Jul/0086.html

Basically 303 redirects totally mess with any efforts to undertake SEO and significantly complicate google analytics.

They also represent a challenge in producing rdfa representations that link across pages in a search engine crawler friendly fashion.

Cheers,

Mark


Sent from my iPhone

> On 23 Jul 2014, at 9:22 pm, "john.walker" <john.walker@semaku.com> wrote:
> 
> Hi There,
>  
> There is plenty of advice/help out there regarding URI schemes for instance
> data, for example the EC study on persistent URIs [1].
>  
> I was wondering if there are any similar studies or guidelines about URI schemes
> for RDF schema (using this as catch all term for vocabulary, data dictionary,
> schema, ontology).
>  
> The particular use case I have is a ISO 13584 compliant data dictionary with a
> few hundred classes and over 1000 properties which I'd like to convert to RDF.
> Everything in the dictionary (including the dictionary itself) is identified
> with an IRDI [2].
>  
> Points to consider:
> 
> 1. (I'll get this one out of the way first :) ) Hash vs. slash URIs: What's the
> latest advice/pros/cons? Currently I am leaning towards slash URIs so the user
> is not forced to download the entire schema in one file (of course we can always
> provide a dump for those who want it). Any best practices here?
> 
> 2. URN or HTTP URI: A URN scheme for IRDIs has previously been mooted, but seems
> a distinct lack of progress. Following linked data principles I was planning to
> use HTTP URIs instead. Would there be any advantage to use URNs instead?
> 
> 3. Human-readable URIs: Many widely used schema (e.g. Schema.org, FOAF) have a
> human-readable component in the URI, typically a URI-friendly version of the
> label. I can see this makes things a lot easier for human consumers when reading
> raw Turtle or writing a SPARQL query. However the labels are subject to change
> over time, are in multiple languages and are not unique. It is simple to define
> a mapping from IRDI to URI, but this does not give a meaningful URI (e.g.
> http://example.com/myDictionary/c_abc123), but would guarantee uniqueness and
> persistence. Given the opacity axiom [3] does this really matter? I could
> imagine that one could allow the editor of the dictionary to define slugs that
> would be to build the URI rather than generating from the IRDI. These could be
> optional and you might only define such a slug for the most commonly used terms.
> Alternatively one could define these as aliases with additional statements
> defining some equivalence links (perhaps using owl:sameAs, owl:equivalentClass
> and owl:equivalentProperty).
> 
> <http://example.com/myDictionary/c_abc123> owl:equivalentClass
> <http://example.com/myDictionary/Person> .
> 
> Has anyone ever tried such an approach?
> 
> 4. Versioning: The IRDI includes a version identifier where there are clearly
> defined rules about what type of change can be done within a version (e.g.
> editorial changes), what can be done as a version change (e.g. upward-compatible
> change) and what requires a new identifier (breaking change). I was thinking to
> exclude this version identifier from the URI, but perhaps (if needed) expose the
> different versions/states of the resource using Memento [4]. Any experiences
> with using such an approach?
> 
> 5. Serving representations: Maybe this is a moot point, but I would consider the
> 'things' described in the dictionary to be abstract entities and, as such, to
> give a 303 response if used with slash URIs. The response would then include a
> redirect to the information resource that would use conneg to serve the
> different representations/states of that resource. However I do not see this
> practice widely used for other RDF schemas. Any reason why?
>  
> [1] http://philarcher.org/diary/2013/uripersistence/
> [2] http://wiki.eclass.eu/wiki/IRDI
> [3] http://www.w3.org/DesignIssues/Axioms.html#opaque
> [4] http://mementoweb.org/
>  
> Regards,
> 
> John Walker
>