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Re: Meaning of property "url"

From: Cord Wiljes <cwiljes@cit-ec.uni-bielefeld.de>
Date: Mon, 10 Sep 2012 14:14:42 +0200
Message-ID: <504DD9B2.4070705@cit-ec.uni-bielefeld.de>
To: public-vocabs@w3.org
 From http://www.schema.org/docs/gs.html

    <div itemscope itemtype="http://schema.org/Book">
       <span itemprop="name">The Catcher in the Rye</span>---
       by <span itemprop="author">J.D. Salinger</a>
       Here is the book's <a itemprop="url" href="http://en.wikipedia.org/wiki/The_Catcher_in_the_Rye">Wikipedia page</a>.
    </div>

In this example "url" does not contain the location of a file with the 
book's text but rather the URL of the Wikipedia page (a page with 
information on the book). So I assume this would also be O.K.:

    <div itemscope itemtype="http://schema.org/Person">
       <span itemprop="name">Cord Wiljes</span>
       Here is <a itemprop="url" href="http://www.wiljes.de/cord">Cord's Homepage</a>.
    </div>

Cord

Am 10.09.2012 13:27, schrieb Cord Wiljes:
> Hi Michael,
> > (schema.org's "url" property) means something very specific:
> > "this is the Web location of" _____ (where ______ is some network
> > addressable digital file).
> That is what I thought, too. But the I wonder why:
>
>   * "url" is a property of class "Thing" (instead of just class
>     "CreativeWork")
>   * there is no property "homepage" for class "Person" or "website"
>     for class "Organization"
>
> Cord
>
>
> Am 10.09.2012 12:31, schrieb Michael Hopwood:
>> Cord,
>>
>> This is the URI / URL / URN discussion again.
>>
>>>>> Or in other words: "url" means something rather general: "There is a web document related to the resource that can be retrieved at this url."
>> The opposite, it means something very specific: "this is the Web location of" _____ (where ______ is some network addressable digital file).
>>
>> A URI is just a Web syntax used to identify stuff because the HTTP syntax conveniently allows you
>>
>> a) control over the lookup so you can put some description there (as you said);
>>
>> b) uniqueness also because of a) and the way the HTTP is set up.
>>
>> HTTP URI is paradoxically a very general protocol with very limited application ;)
>>
>> What is lacking is the infrastructure to ensure persistence, quality of lookup and a lot of other things. Most URNs in practical application have those but without the nice HTTP aspect, but in principle they can get it as an added service (e.g. ISBN-A).
>>
>> DOI is an attempt to add all those features together an generalise to the entire Web.
>>
>> Cheers,
>>
>> M
>>
>> -----Original Message-----
>> From: Cord Wiljes [mailto:cwiljes@cit-ec.uni-bielefeld.de]
>> Sent: 10 September 2012 11:17
>> To:public-vocabs@w3.org
>> Subject: Re: new itemscope or not?
>>
>> The schema.org specification seems to support Jeff's interpretation of the property "url" as "the WWW-address where an electronic copy of the thing that s described can be downloaded". From
>> http://www.schema.org/Thing:
>>
>> Property: url
>> Expected Type: URL
>> Description: URL of the item.
>>
>> Only something that can be downloaded (an information resource) can have a URL. So schema.org's property "url" should only be available for "CreativeWork", not for "Thing" as it is right now. A person for example can't have a url. A person can have a website (which is an information
>> resource) and this website has an url. But then I cannot find any property like "website" or "homepage" for any of schema.org's classes.
>> Combined with the fact that "url" is avalable for class "Thing" (i.e.
>> for everything) I suppose that "url" is in fact used ambiguosly:
>>
>> A book can have a url where you can download the book's text.
>> A person can have a url where you find information about this person.
>>
>> Or in other words: "url" means something rather general: "There is a web document related to the resource that can be retrieved at this url."
>> Essentially its just a "see also" to a document on the web.
>>
>> Cord
>>
>>
>> Am 08.09.2012 04:14, schrieb Young,Jeff (OR):
>>> If I was Godz, I would NOT assume they are the same thing. I would use
>>> schema:url thusly for those decreasingly rare situations where
>>> somebody (especially a remote observer) wants to describe something
>>> that is honest-to-godz located on the Web. For example:
>>>
>>> @prefix observer:<http://example.org/observer/>  .
>>>
>>> observer:12345 a<http://purl.org/library/Thesis>;
>>> 	schema:name "Architectural Styles and the Design of Network-based
>>> Software Architectures";
>>> 	schema:author<http://viaf.org/viaf/26681119>;
>>> 	schema:url
>>> <http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm>.
>>>
>>> As a matter of principle, Roy's (HTML) thesis COULD be upgraded to be
>>> self-describing with some hidden markup (either RDFa 1.1 or Microdata)
>>> and a trivial Apache rewrite (303 redirect) upgrade towww.ics.ici.edu  
>>> to replace the observer URI.
>>>
>>> OTOH, if somebody decides that schema:url should be treated the same
>>> as "itemid" (Microdata), "resource" (RDFa Lite 1.1), "rdf:about"
>>> (RDF/XML), etc. then schema:url is a wasted opportunity and we (i.e.
>>> the pedantic observers of reality) would need to find a new vocabulary
>>> term fill this void.
>>>
>>> Jeff
>>>
>>>> -----Original Message-----
>>>> From: Jeni Tennison [mailto:jeni@jenitennison.com]
>>>> Sent: Friday, September 07, 2012 3:15 PM
>>>> To: Ed Summers
>>>> Cc: Dawson, Laura; Thad Guidry;public-vocabs@w3.org
>>>> Subject: Re: new itemscope or not?
>>>>
>>>>
>>>> On 7 Sep 2012, at 20:03, Ed Summers wrote:
>>>>> It would be interesting to know if the HTML spec allowed multiple
>>>>> identifiers, similar to how other HTML attributes work:
>>>> "The itemid attribute, if specified, must have a value that is a
>>>> valid URL potentially surrounded by spaces."
>>>>
>>>> http://www.w3.org/TR/microdata/#attr-itemid
>>>>
>>>> So that would be 'no', not according to spec.
>>>>
>>>> I've often wondered whether the schema.org 'url' property is meant to
>>>> be synonymous with itemid. I'm not sure what happens in schema.org
>>>> interpreters when you specify one/other/both/multiple urls...
>>>>
>>>> Jeni
>>>> --
>>>> Jeni Tennison
>>>> http://www.jenitennison.com
>>>>
>>>>
>> --
>> Cord Wiljes
>> Semantic Computing Group
>> Excellence Cluster - Cognitive Interaction Technology (CITEC) Bielefeld University
>>
>> Phone: +49 521 106 12036
>> Mail:cwiljes@cit-ec.uni-bielefeld.de
>> WWW:http://www.sc.cit-ec.uni-bielefeld.de/people/wiljes
>>
>> Room H-123
>> Morgenbreede 39
>> 33615 Bielefeld
>>
>>
>>
>
>
> -- 
> Cord Wiljes
> Semantic Computing Group
> Excellence Cluster - Cognitive Interaction Technology (CITEC)
> Bielefeld University
>
> Phone: +49 521 106 12036
> Mail:cwiljes@cit-ec.uni-bielefeld.de
> WWW:http://www.sc.cit-ec.uni-bielefeld.de/people/wiljes
>
> Room H-123
> Morgenbreede 39
> 33615 Bielefeld


-- 
Cord Wiljes
Semantic Computing Group
Excellence Cluster - Cognitive Interaction Technology (CITEC)
Bielefeld University

Phone: +49 521 106 12036
Mail: cwiljes@cit-ec.uni-bielefeld.de
WWW: http://www.sc.cit-ec.uni-bielefeld.de/people/wiljes

Room H-123
Morgenbreede 39
33615 Bielefeld
Received on Monday, 10 September 2012 12:15:12 GMT

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