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

Hi Bernard, Hugh and All,

<left-field>
The example in which there are three distinct things called Berlin raises an
interesting question.

The question is, why would it be a good idea to try to make sense of this at
the data + ontology level?

I ask because, implicit in the attempt lurks the notion that there is a way
of doing this that will be 'correct' for all future applications over the
data + ontology.

That seems just plain wrong, even for this simple example.

The inconvenient truth is that applications add semantics to the data +
ontology layers.  Shifting representations to recognize this could be hugely
productive.

</left-field>

Just my two cents.

                        -- Adrian

Internet Business Logic
A Wiki and SOA Endpoint for Executable Open Vocabulary English over SQL and
RDF
Online at www.reengineeringllc.com
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Adrian Walker
Reengineering

On Tue, Apr 27, 2010 at 11:38 AM, Bernard Vatant <bernard.vatant@mondeca.com
> wrote:

> 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.org re. 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
>
> Bernard
>
>
>
>> 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
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