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Re: Figuring out what's behind a SPARQL endpoint

From: Michael Hausenblas <michael.hausenblas@deri.org>
Date: Tue, 23 Mar 2010 08:22:22 +0000
To: "Hondros, Constantine" <Constantine.Hondros@wolterskluwer.com>
CC: Linked Data community <public-lod@w3.org>
Message-ID: <C7CE2ABE.E7F5%michael.hausenblas@deri.org>
Constantine,

> These queries give me some indication of what's there ... but  what would be
> handy is some sort of visualisation or analysis tool that gives me statistics
> like the number of resources contained in the endpoint, the type and predicate
> vocabularies used, and the density of linking between resources.
> 
> Anything like this exist?

Short answer: 

Yes, the voiD vocabulary and voiD tool set [1]-[6] as well as the W3C SPARQL
service description [7].

Longer answer:

There are two answers to it, IMO: first, the metadata regarding the
datasets, which is covered by voiD, the vocabulary of interlinked datasets
[1],[2],[3] - there are dedicated stores [4], [5] where you can find the
descriptions and you'll also be able to find the voiD descriptions via
general-purpose semantic indexers such as Sindice. There are also voiD tools
that allow you to generate voiD descriptions [6].

The second part is related to SPARQL itself. I can only point you into the
direction as I'm not directly involved in this activity: the W3C SPARQL
Working Group is working on "SPARQL 1.1 Service Description" [7].

BTW:  we take care of making sure that voiD plays nicely together with the
W3C service description stuff ;)

Cheers,
      Michael

[1] http://semanticweb.org/wiki/VoiD
[2] http://rdfs.org/ns/void/
[3] http://rdfs.org/ns/void-guide
[4] http://void.rkbexplorer.com/
[5] http://kwijibo.talis.com/voiD/
[6] http://lab.linkeddata.deri.ie/ve2/
[7] http://www.w3.org/TR/sparql11-service-description/

-- 
Dr. Michael Hausenblas
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



> From: "Hondros, Constantine" <Constantine.Hondros@wolterskluwer.com>
> Date: Tue, 23 Mar 2010 08:59:02 +0100
> To: Linked Data community <public-lod@w3.org>
> Subject: Figuring out what's behind a SPARQL endpoint
> Resent-From: Linked Data community <public-lod@w3.org>
> Resent-Date: Tue, 23 Mar 2010 07:59:40 +0000
> 
> What's the best way to get a grip on what's actually behind an endpoint?
> 
> I've been mulling over a proof-of-concept project to enrich published legal
> content - already highly annotated with RDF metadata - with RDF content from
> open government sources. But I'm kind of baffled by how best to assess the
> richness of an endpoint other than by running my own SPARQLs - eg. listing
> DISTINCT predicates, or CONSTRUCTing some of the typed resources.
> 
> These queries give me some indication of what's there ... but  what would be
> handy is some sort of visualisation or analysis tool that gives me statistics
> like the number of resources contained in the endpoint, the type and predicate
> vocabularies used, and the density of linking between resources.
> 
> Anything like this exist?
> 
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Received on Tuesday, 23 March 2010 08:22:55 UTC

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