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Re: Semantics of rdfs:seeAlso (Was: Is it best practices to use a rdfs:seeAlso link to a potentially multimegabyte PDF?)

From: Nathan <nathan@webr3.org>
Date: Thu, 13 Jan 2011 18:16:57 +0000
Message-ID: <4D2F4199.9080400@webr3.org>
To: Kingsley Idehen <kidehen@openlinksw.com>
CC: Tim Berners-Lee <timbl@w3.org>, Martin Hepp <martin.hepp@ebusiness-unibw.org>, Linked Open Data <public-lod@w3.org>
Kingsley Idehen wrote:
> On 1/13/11 12:04 PM, Nathan wrote:
>> Hi Kinglsey,
>>
>> Kingsley Idehen wrote:
>>> When our engine describes entities it can publish these descriptions 
>>> using variety of structured data formats that include RDF. The same 
>>> thing applies on the data consumption side. Basically, RDF formats 
>>> are options re. Linked Data (the concept).
>>
>> A generic problem here, when using non RDF types with Linked Data over 
>> HTTP, is that there's currently no way to indicate that a resource 
>> is/has a set of machine readable "linked data" variants, in many cases 
>> it is useful to publish and consume with linked data in CSV format and 
>> related (as you well note) - but without prior out of band knowledge 
>> that the representation contains, or is, linked data, the machines are 
>> pretty much screwed. Typically the RDF variants don't have this 
>> problem because the media type sets the expectation, so you can conneg 
>> on an RDF type and know your getting back "linked data", you can't do 
>> this with CSV and related with any expectation that you'll get back 
>> "linked data" - thus, if there was some way to mark the set of 
>> representations given upon dereferencing a URI as linked data, 
>> containing rdf, rdfable 3 tuples, or a view thereof, it'd be a lot 
>> friendlier to the web of data in general.
> 
> So what happens to RDFa in (X)HTML? Even worse, no DOCTYPE declarations?
> What about various JSON dialects for Linked Data graphs?
> How about N-Triples? Ditto TriX and others?

Probably wasn't clear, I'm saying there needs to be something (for 
instance a new header) which indicates that the representation contains 
"linked data", then you machines could automatically throw the CSV 
through a csv-linked-data parser and it'd work, likewise every type you 
mentioned above.

The problem here isn't the different types of media, the problem here is

(1) internet media types are dire and badly need re-looked at

(2) there's no information provided to machine so that it has a hope in 
hell of understanding one of these other variants (lest it has it's own 
special mediatype)

Fix that and the door is opened to all of the above.

  - RDFa needs an indicator at HTTP Message level to say it's "html+rdfa"
  - JSON dialects need standardized (coming soon to a WG near you) w/ 
media type registered / well-known
  - N-Triples needs it's own media type (doesn't have one)
  - and so on..

Typically we need a machine to not only ask "Accept: something/rdf" but 
to effectively ask "if linked data give me JSON" (swap json for csv, 
turtle, rdf+xml, whatever)

Best,

Nathan
Received on Thursday, 13 January 2011 18:18:07 UTC

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