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

Re: Dataset URIs and metadata.

From: Michael Hausenblas <michael.hausenblas@deri.org>
Date: Fri, 22 Jul 2011 09:59:40 +0100
Cc: public-lod@w3.org
Message-Id: <137BC7FE-A6A8-463D-B755-DEFBD8C80078@deri.org>
To: Frans Knibbe <frans.knibbe@geodan.nl>

Frans,

> I had a quick look. But I could not find it. I had a closer look now  
> and I see the URI probably is http://dbpedia.org/void/Dataset. I  
> have tried it. Redirection to either HTML or RDF seems to be in  
> place. HTML request lead to http://dbpedia.org/void/page/Dataset,  
> which shows a table of VoID properties. The RDF redirection (to http://dbpedia.org/void/data/Dataset.rdf) 
>  does not seem to work, I get an error.

Sorry, you lost me here. Did you curl it or how did you get your  
findings?

> Apart from the error, somehow this is not what I expected. I assumed  
> that the dataset URI is the URI of a dataset. It is the key to all  
> other data. If you want something from a dataset, you only need to  
> know this URI. So why is the dataset URI hard to find? Why isn't it  
> used when references are made to DBpedia? Why isn't it the same as  
> the base URI (http://dbpedia.org)?.

<http://lod-cloud.net/dbpedia> a void:Dataset;
                                foaf:homepage <http://dbpedia.org/>;

Says everything, or?

> Probably VoID metadata/dataset URIs will be easier to discover once  
> the /.well-known/void trick (described in paragraph 7.2 of the W3C  
> VoID document) is widely adopted.

Agreed. But it's not a 'trick'. It's called a standard.

Cheers,
	Michael
--
Dr. Michael Hausenblas, Research Fellow
LiDRC - Linked Data Research Centre
DERI - Digital Enterprise Research Institute
NUIG - National University of Ireland, Galway
Ireland, Europe
Tel. +353 91 495730
http://linkeddata.deri.ie/
http://sw-app.org/about.html

On 22 Jul 2011, at 09:42, Frans Knibbe wrote:

> On 2011-07-21 16:27, Michael Hausenblas wrote:
>>
>>
>>> But is this really common practice nowadays? Take DBpedia for  
>>> example. What is the URI of the DBpedia dataset? Is it http://dbpedia.org? 
>>>  That does not seem to resolve to a set of metadata.
>>
>> Did you have a look at the URI I gave you? I mean http://lod-cloud.net/void.ttl
> I had a quick look. But I could not find it. I had a closer look now  
> and I see the URI probably is http://dbpedia.org/void/Dataset. I  
> have tried it. Redirection to either HTML or RDF seems to be in  
> place. HTML request lead to http://dbpedia.org/void/page/Dataset,  
> which shows a table of VoID properties. The RDF redirection (to http://dbpedia.org/void/data/Dataset.rdf) 
>  does not seem to work, I get an error.
>
> Apart from the error, somehow this is not what I expected. I assumed  
> that the dataset URI is the URI of a dataset. It is the key to all  
> other data. If you want something from a dataset, you only need to  
> know this URI. So why is the dataset URI hard to find? Why isn't it  
> used when references are made to DBpedia? Why isn't it the same as  
> the base URI (http://dbpedia.org)?.
>
> Probably VoID metadata/dataset URIs will be easier to discover once  
> the /.well-known/void trick (described in paragraph 7.2 of the W3C  
> VoID document) is widely adopted.
>
>>
>> BTW, some 30% [1] of the LOD cloud datasets are using VoID ...
>>
>>> Is there a general way of obtaining datasets URIs?
>>
>> Not to my knowledge. We're working on it in LATC [2] - Keith?
>>
>> Cheers,
>>     Michael
>>
>> [1] http://www4.wiwiss.fu-berlin.de/lodcloud/state/#data-set-level-metadata
>> [2] http://latc-project.eu/
>>
>> -- 
>> Dr. Michael Hausenblas, Research Fellow
>> LiDRC - Linked Data Research Centre
>> DERI - Digital Enterprise Research Institute
>> NUIG - National University of Ireland, Galway
>> Ireland, Europe
>> Tel. +353 91 495730
>> http://linkeddata.deri.ie/
>> http://sw-app.org/about.html
>>
>> On 21 Jul 2011, at 15:19, Frans Knibbe wrote:
>>
>>>
>>> Thanks for the replies. It seems that there is agreement that a  
>>> dataset should have a URI and that dereferencing that URI should  
>>> return metadata about the dataset. That is good to know.
>>>
>>> But is this really common practice nowadays? Take DBpedia for  
>>> example. What is the URI of the DBpedia dataset? Is it http://dbpedia.org? 
>>>  That does not seem to resolve to a set of metadata.
>>>
>>> Is there a general way of obtaining datasets URIs?
>>>
>>> I can imagine an RDF dataset comprising all known dataset URIs.  
>>> And of course that dataset will have a URI itself. Does such a  
>>> dataset exist at the moment?
>>>
>>> Regards,
>>> Frans
>>>
>>>
>>> On 2011-07-21 12:35, Frans Knibbe wrote:
>>>>
>>>> Hello,
>>>>
>>>> I have just placed a Linked Data dataset online and now I am  
>>>> struggling with finding the best way to publish the metadata of  
>>>> the dataset. I wonder if there are best practices for referencing  
>>>> a dataset and its metadata, and for linking the two.
>>>>
>>>> I did find out that using the Vocabulary of Interlinked Data  
>>>> (VoID) is a good way to publish the metadata of a dataset. But I  
>>>> still need some guidance. I have come up with three questions:
>>>>
>>>> 1) Is it common practice/recommendable to regard a dataset a  
>>>> resource? If it is, then all datasets should have a URI, right?
>>>> 2) If having a dataset URI is a good thing, what should be behind  
>>>> the URI? Should dereferencing the URI lead to the dataset  
>>>> metadata (a VoID file for example)?
>>>> 3) If dereferencing a dataset  URI leads to the dataset metadata,  
>>>> should there be separate HTML and RDF versions of the metadata?  
>>>> Or is it better to have a HTML page with embedded (RDFa) RDF data?
>>>>
>>>> Thanks in advance for your help,
>>>> Frans
>>>
>>
>>
>
>
Received on Friday, 22 July 2011 09:00:21 UTC

This archive was generated by hypermail 2.3.1 : Sunday, 31 March 2013 14:24:34 UTC