Hi Hugh
2010/4/27 Hugh Glaser h...@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
Bernard
Best
Hugh
On 23/04/2010 16:14, Bernard Vatant bernard.vat...@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.9202a8c04000641f800094d6
* 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
