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Re: [Linking-open-data] watchdog.net and LOD best practices

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Wed, 16 Apr 2008 11:05:34 -0400
Message-ID: <480615BE.60101@openlinksw.com>
CC: Peter Ansell <ansell.peter@gmail.com>, public-lod@w3.org

Tom Heath wrote:
> Ed,
>
> Thanks for asking the question - it's a good one, and I'd also be keen
> to hear the background to this decision from Aaron. As you flag up in
> your response re the use of #this, the issue here is much more about
> distinguishing Districts from "Documents about Districts" than it is
> about slashes or hashes.
>
> Tom.
>
>   
Tom,

Yes.

I see Peter is here :-) I've been trying to drive home this issue of 
Identity and Address separation. The URI <> URL unless he "Thing" in 
question is an information resource, and only then is appropriate to 
take the URI/URL approach.

A Web of Data is a Web of Data Objects. The Document Web is a Web of 
Documents.  In either case you must uniquely identify the Objects :-)

#this is just a cheap mechanism for making a URI from a URL without the 
cost of a 303 .

We have to do a better job of explaining what Object Identity is about 
in the context of the Linekd Data Web, especially as this is an area of 
computer science that predates the Web.

Kingsley
>   
>> -----Original Message-----
>> From: public-lod-request@w3.org 
>> [mailto:public-lod-request@w3.org] On Behalf Of Ed Summers
>> Sent: 16 April 2008 00:33
>> To: Peter Ansell
>> Cc: public-lod@w3.org
>> Subject: Re: [Linking-open-data] watchdog.net and LOD best practices
>>
>>
>> On Tue, Apr 15, 2008 at 6:21 PM, Peter Ansell 
>> <ansell.peter@gmail.com> wrote:
>>     
>>>  The insistence on slash URI's having 303 is mostly 
>>>       
>> philosophical if  
>>     
>>> you are still going to allow hash URI's which people have no real  
>>> reason to go away from. When you consider that user agents 
>>>       
>> do not send  
>>     
>>> the hash part anyway, hence you have no idea at the server whether  
>>> they are wanting the resource or just part, so you send back the  
>>> result of a slash URL resolution... No need to push someone away  
>>> because they didn't follow and arbitrary rule for "non-information  
>>> resources".
>>>       
>> I'm really not trying to push anyone away -- and I apologize 
>> if it appeared that I was. My exposure to linking data has 
>> largely been informed by watching discussions on here and 
>> reading documents like How to Publish Linked Data on the Web 
>> [1] and Cool URIs for the Semantic Web [2].
>>
>> The value of these documents IMHO, is that the provide some 
>> pretty clear guidance on URI design w/ httpRange-14 in mind. 
>> I know Aaron is not a newcomer to the web or RDF -- so I was 
>> genuinely curious about the thought process behind the service.
>>
>>     
>>> If there is any experimental evidence the Semantic Web  
>>>       
>> will actually 
>>     
>>> succeed if there are double the number of requests  needed for a 
>>> single resolution then it may be interesting to revisit  
>>>       
>> the idea of 
>>     
>>> assuming people are bad semantic web citizens because they  
>>>       
>> implement 
>>     
>>> things pragmatically.
>>>       
>> That's why the hash option is there. I'm fairly certain that 
>> the watchdog rdf descriptions would just have to use a hash 
>> URI in the description to be compliant--no double requests or 
>> 303 is necessary.
>> For example:
>>
>> @prefix : <http://watchdog.net/about/api#> .
>>
>> <http://watchdog.net/us/MD-08#this> a :District;
>>   :almanac 
>> <http://nationaljournal.com/pubs/almanac/2008/people/md/rep_md08.htm>;
>>   :area_sqmi 307;
>>   :center_lat 39.0231;
>>   :center_lng -77.1421;
>>   :cook_index "D+20";
>>   :est_population 700364;
>>   :est_population_year 2005;
>>   :median_income 68306;
>>   :name "MD-08";
>>   :poverty_pct 6.2;  :state <http://watchdog.net/us/md>;  
>> :voting true;  :wikipedia 
>> <http://en.wikipedia.org/wiki/Maryland's_8th_congressional_district>;
>> :zoom_level 10;.
>>
>>     
>>>  It would however be nice to have link rel="alternate"
>>>  type="application/rdf+xml" href="blah.xml" etc. in the 
>>>       
>> head of the  
>>     
>>> html though to facilitate the discovery of the RDF/N3/JSON 
>>>       
>> materials  
>>     
>>> automatically. That doesn't imply that the blah.xml has to 303  
>>> redirect to a third resource "just in case" though.
>>>       
>> Right it doesn't have to. But the URI used to identify a 
>> district would just need a hash part appended to it as above. 
>> I'm not really trying to pedantic here, I'm trying to 
>> understand the best practices myself.
>>
>> //Ed
>>
>> [1] http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/
>> [2] http://www.w3.org/TR/cooluris/
>>
>>
>>     
>
>
>   


-- 


Regards,

Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software     Web: http://www.openlinksw.com
Received on Wednesday, 16 April 2008 15:06:13 UTC

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