On 11.03.2015 05:40, Tom Morris wrote:
On Tue, Mar 10, 2015 at 6:41 PM, Markus Krötzsch
<markus(a)semantic-mediawiki.org <mailto:markus@semantic-mediawiki.org>>
wrote:
For example, you can see that Portugal has a lot of lighthouses
while Spain has almost none -- maybe we need to look at our data
there ;-)
Perhaps it's a language confusion issue, but does Spain really have few
lighthouses? That would seem VERY unusual for a territory with an
extensive coastline.
No, you are right: this is of course an issue in the completeness of our
data. If you zoom in to Europe, you can see that some countries have
costs full of lighthouses, while others seem to lack them almost
completely. I think it clearly shows that a lot of our data comes from
Wikipedias (in some specific language).
Where does Wikidata sit in that mix? How does it compare with DBpedia,
Freebase, Wikipedia, or even *real* data sources like official
governmental lists of navigational aids for mariners at sea?
Good question. I guess that we could have a much better coverage for
some of the obvious holes in our data, e.g., by adding classificaiton
information based on Spanish Wikipedia categories.
Independent of where it sits now, what where does it aspire to sit?
The uncontested target would be:
* Every lighthouse that is found in any Wikipedia (hence in Wikidata)
should be "instance of lighthouse" and have coordinates and country defined.
A possible target to discuss would be to add:
* Every lighthouse should be in Wikidata.
Whether or not this makes sense depends on how many lighthouses there
really are. Maybe we are not so far from completeness. Lighthouses are
prominent landmarks of historic, nautic, and touristic interest, so
should be valid Wikipedia topics anyway. Moreover, they tend to change
very little over time, so data maintenance is relatively easy.
Note that this is quite different from streets, which change names all
the time, get created, demolished, and merged, and are much larger in
number. From these properties, I think OSM is much better suited for
managing this data for now.
In view of the current developments towards Wikidata query support, a
tangible goal would be to set up integrated query services that provide
a joint view of the data from OSM and Wikidata without physically moving
large quantities of data from one to the other.
Markus
