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Re: Semantic black holes at sameas.org Re: [GeoNames] LOD mappings

From: Bernard Vatant <bernard.vatant@mondeca.com>
Date: Tue, 27 Apr 2010 17:38:24 +0200
Message-ID: <s2y9d93ef961004270838xaa0eda6fwb64e4deb83c929d0@mail.gmail.com>
To: Hugh Glaser <hg@ecs.soton.ac.uk>
Cc: geonames <geonames@googlegroups.com>, Linking Open Data <public-lod@w3.org>
Hi Hugh

2010/4/27 Hugh Glaser <hg@ecs.soton.ac.uk>

> Thanks Bernard.
> Yes, I think the problems you raise are valid.
> Just a short response.
> In some sense I consider sameas.org to be a discovery service.

Indeed, so do I. The known issue is the overload of owl:sameAs, but you have
an excellent presentation today of Pat Hayes and Harry Halpin just coming
... (you are at ldow2010 I guess)

> This is in contrast to a service that might be called something more
> definitive.
> So I have taken quite a liberal view of what I will accept on the site.

We have other services that are much more conservative in their view; in
> particular the ones we use for RKBExplorer.
> So what we are trying to do is capture a spectrum of views of what
> constitutes equivalence, which will always be a moveable feast.

Agreed with all that. Maybe you could introduce a sameas ontology for
different flavours of equivalence, containing a single property
sameas:sameas  of which owl:sameAs; owl:equivalent*, skos:*Match ... would
be subproperties. In that case the "liberal" clustering would use
sameas:sameas and the more conservative ones whatever fits.

BTW currently working in connection with Gerard de Melo at
http://lexvo.orgre. semiotic approach to this issue, connecting
vocabulary resources
(concepts, classes, whatever) through the terms they use. You might bring
that on ldow forum.

Have fun


> Best
> Hugh
> On 23/04/2010 16:14, "Bernard Vatant" <bernard.vatant@mondeca.com> wrote:
> Alexander :
> It would be useful to have a list of currently available mappings to
> GeoNames. It would be useful not only for people like me who create custom
> RDF datasets but also for people who want to contribute additional mappings.
> Seems a good idea
> Daniel :
> Re-publish your data with rdfs:seeAlso
> http://sameas.org/rdf?uri=http%3A%2F%2Fsws.geonames.org%2F2078025%2Fperhaps?
> This seems like a good idea. Considering that geonames.org <
> http://geonames.org>  cannot dedicate (m)any resources to LOD mappings,
> those can be deferred to external services such as sameas.org <
> http://sameas.org> . The sameas.org <http://sameas.org>  URI is easy to
> generate automatically from the geonames id.
> So far so good. But let's look at it closely. Someone has to feed this kind
> of recursive and iterative social process happening at sameas.org <
> http://sameas.org> , but there is no provenance track, and the clustering
> of URIs will make with the time the concepts more and more fuzzy, and
> sameas.org <http://sameas.org>  a tool to create semantic black holes.
> It would be definitely better to have some clear declaration from Geonames
> viewpoint which of its three URIs for Berlin
> http://sws.geonames.org/2950159/, http://sws.geonames.org/6547383/ or
> http://sws.geonames.org/6547539/ should map to
> http://dbpedia.org/resource/Berlin. So far, neither does.
> From DBpedia side owl:sameAs declarations at the latter URI are as
> following (today)
>   *   opencyc:en/Berlin_StateGermany <
> http://sw.opencyc.org/2008/06/10/concept/Mx4rv77EfZwpEbGdrcN5Y29ycA>
>  *   fbase:Berlin <
> http://rdf.freebase.com/ns/guid.9202a8c04000641f80000000000094d6>
>  *   http://umbel.org/umbel/ne/wikipedia/Berlin
>  *   opencyc:en/CityOfBerlinGermany <
> http://sw.opencyc.org/2008/06/10/concept/Mx4rvVjrhpwpEbGdrcN5Y29ycA>
>  *   http://www4.wiwiss.fu-berlin.de/eurostat/resource/regions/Berlin
>   *   http://sws.geonames.org/2950159/
>  *   http://data.nytimes.com/N50987186835223032381
> So it seems DBpedia has decided to map its Berlin to the Geonames feature
> of type "capital of a political entity", subtype of "populated place". Why
> not? OTOH it also declares two equivalent in opencyc, one being a state and
> the other a city. If opencyc buys the DBpedia declarations, the semantic
> collapse begins
> Let's go yet closer to the black hole horizon ...
> http://sameas.org/html?uri=http%3A%2F%2Fdbpedia.org%2Fresource%2FBerlin
> ... yields 29 URIs including the previous ones ...
> If geonames.org <http://geonames.org>  had taken the time to map carefully
> its administrative features on the respective "city" and "state" opencyc
> resources, the three different URIs carefully coined to make distinct
> entities for Berlin as a populated place and the two administrative
> subdivisions bearing the same name, would be by the grace of DBpedia
> fuzziness crushed in the same sameas.org <http://sameas.org>  semantic
> black hole.
> Bottom line. Given the current state of affairs for geographical entities
> in the linked data cloud, geonames agnosticism re. owl:sameAs is rather a
> good thing. There are certainly more subtle ways to link geo entities at
> various level of granularity, and a lot of work to achieve semantic
> interoperability of geo entities defined everywhere. Things are moving
> forward, but it will be a long way and needin a lot of resources. Look e.g.,
> at Yahoo! concordance
> http://developer.yahoo.com/geo/geoplanet/guide/api-reference.html#api-concordance,
> which BTW also links to geonames id.
> In conclusion:
> YES Marc Wick is right to currently focus on data and data quality first. A
> tremendous set of data is available for free, take what you can and what you
> wish and build on it. If you want premium services, pay for it. Fair enough.
> YES it should be great to have geonames data/URIs more integrated, and
> better to the linked data economy. More complete descriptions at
> sws.geonames URIs, SPARQL endpoint etc. Bearing in mind that Geonames.org
> has no dedicated resources for it, who will care of that in a scalable way?
> What is the business model? Good questions. Volunteers, step forward :)
> Bernard

Bernard Vatant
Senior Consultant
Vocabulary & Data Engineering
Tel:       +33 (0) 971 488 459
Mail:     bernard.vatant@mondeca.com
3, cité Nollez 75018 Paris France
Web:    http://www.mondeca.com
Blog:    http://mondeca.wordpress.com
Received on Tuesday, 27 April 2010 15:38:58 UTC

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