W3C home > Mailing lists > Public > public-lod@w3.org > January 2011

Re: Is it best practices to use a rdfs:seeAlso link to a potentially multimegabyte PDF?, existing predicate for linking to PDF?

From: Martin Hepp <martin.hepp@ebusiness-unibw.org>
Date: Thu, 13 Jan 2011 11:10:26 +0100
Cc: Tim Berners-Lee <timbl@w3.org>, Vasiliy Faronov <vfaronov@gmail.com>, Toby Inkster <tai@g5n.co.uk>, Peter DeVries <pete.devries@gmail.com>, public-lod@w3.org
Message-Id: <CF47D2E2-6071-4120-85CD-2ED53FFF404E@ebusiness-unibw.org>
To: nathan@webr3.org
Hi Nathan:

> There are other ways of looking at this, remembering we're in the  
> realm of machine readable information and the context of RDF.  
> rdfs:seeAlso is used to indicate a resource O which may provide  
> additional information about the resource S - information in this  
> context being rdf, information for the machine - so we can say that  
> if O points to a resource that doesn't contain any information at  
> all (no rdf, or isn't the subject of any statements) then we've  
> created a meaningless statement, it may as well be { S rdfs:seeAlso  
> [] }
>
> One could easily suggest that it's good for RDF Schema properties to  
> have some use in RDF, and thus that if rdfs:seeAlso is used in a  
> statement, that it should point to some "information", some rdf for  
> the machine, otherwise it's a bit of a pointless property.
>
> Given the above, we could take the meaning of the sentence "no  
> constraints are placed on the format of those representations" and  
> assert that this simply means that RDF/XML is not required, and that  
> any RDF format can be used.

I don't buy in to restricting the meaning of "data" in the context of  
RDF to "RDF data". If the subject or object of RDF triples can be any  
Web resource (information and non-information resource), then the  
range of rdfs:seeAlso should also include information resources (i.e.,  
data) of a variety of conceptual and syntactic forms.

And PDF, HTML without RDFa as well as images clearly qualify as data.  
They are also clearly machine-accessible. If you are still not  
convinced: What about CSV files or text files containing ACE  
(controlled English), or OData / GData?

By the way, the problem of having to load huge amounts of data  
following rdfs:seeAlso is not limited to PDFs - even obeying Tim's  
proposal means there could be huge RDF graphs linked to via  
rdfs:seeAlso, and that is of course conceptually perfectly okay.

After all, rdfs:seeAlso is not  
rdfs:linkToASmallChunkOfVeryRelatedDateInRDF ;-) Data management and  
data quality heuristics should not be solved at the conceptual level.  
If old clients employ outdated heuristics, those clients should update  
their heuristics, IMO.

Best
Martin


On 12.01.2011, at 16:13, Nathan wrote:

> Hi Martin,
>
> Martin Hepp wrote:
>> For my taste, using rdfs:seeAlso is perfectly valid (yet  
>> suboptimal, because too unspecific), according to the RDFS spec:
>> http://www.w3.org/TR/rdf-schema/#ch_seealso
>> Quote: "rdfs:seeAlso is an instance of rdf:Property that is used to  
>> indicate a resource that might provide    additional information  
>> about the subject resource.
>> A triple of the form:
>> S rdfs:seeAlso O
>> states that the resource O may provide additional information about  
>> S. It may be possible to retrieve representations of O from the  
>> Web, but this is not required. When such representations may be  
>> retrieved, ***no constraints are placed on the format of those  
>> representations***."
>
>
>
> Generally it appears to me that rdfs:seeAlso is a property for a  
> machine to follow in order to get more information, and that much of  
> the usage mentioned in this thread requires a property which informs  
> a human that they may want to check resource O for more information  
> - essentially something similar to a hyperlink in a html document  
> with no @rel value.
>
> Best,
>
> Nathan
>
Received on Thursday, 13 January 2011 10:10:58 UTC

This archive was generated by hypermail 2.3.1 : Sunday, 31 March 2013 14:24:31 UTC