Re: [DCAT] accessURLs vs downloadURLs

Hi Luke,

(not an official working group response)

On 6 Nov 2013, at 22:54, Luke Blaney <w3.mailing_lists@lukeblaney.co.uk> wrote:
> The main thing I noticed was the ambiguity between accessURLs and downloadURLs.   I think any spec which contains the words "...when you are not sure whether it is" could do with more clarification.
> Does a downloadURL need to contain the entire dataset, or is it permissible to specify multiple downloadURLs, each containing part of the dataset?  For example, if a dataset contains 3 tables, each downloadable as a separate CSV, can the links to all three be added as downloadURLs?

I’d say no. I read the spec as saying that multiple downloadURLs indicate the same data in different formats.

> The definition of accessURL seems like it could be interpreted to include direct downloads.  Does this mean that downloadURL is a subProperty of accessURL?  If it is, it'd be nice to have an rdfs:subPropertyOf relationship in there.  

This design is, in fact, what I remember from earlier working group discussions, and I was surprised that the spec doesn’t say that downloadURL is a subproperty of accessURL.

> If it isn't, then perhaps the definition of accessURL needs to make this explicit.
> 
> Other than that, I found the inclusion of rdfs:domain on Properties quite inconsistent.  In my view, all rdfs:Properties should have rdfs:domain and rdfs:range specified.

I would agree for any properties defined in the DCAT namespace. In particular, I note that the following properties don’t show an explicit domain, even though their description often implies that they only can be applied to a particular class of entities (catalog, dataset, distribution):

themeTaxonomy
theme
keyword
contactPoint
accessURL
downloadURL
byteSize
mediaType

The ship may have sailed on all of these issues, given that DCAT is in CR stage and that the WG’s charter is running out...

Best,
Richard



> Also, http://www.w3.org/ns/dcat.ttl doesn't seem to match everything at http://www.w3.org/TR/vocab-dcat/  Is there an up-to-date version of the ontology in RDF?
> 
> Regards,
>     Luke Blaney
> 
> P.S. Well done on linking out to other ontologies for existing concepts.  I've noticed a worrying trend recently of people minting their own concepts for everything.

Received on Monday, 11 November 2013 11:56:09 UTC