On 10/28/2011 6:09 PM, Lushan Han wrote:
>
> Question2:
> There is no the class "State" in the dbpedia owl ontology, which is
> very inconvenient. Morevoer, there are many places which are cities
> but do not have "city" type, for example, dbpedia:Beijing. The lowest
> dbpedia-owl class for "Beijing" is still "Settlement"!
>
One of the reasons I like the DBpedia Ontology is that it ducks
the difficult issues; this makes it more possible for DBpedia to be
populated with large amounts of accurate instance data, at least in theory.
A correct ontology of administrative divisions is a difficult
problem because the laws that define administrative divisions are
different in different countries and even inside smaller level
administrative divisions.
In a week or so I'm going to vote for elected officials in an
administrative division called Caroline. Mail to me is addressed to
something called Brooktondale which has no government but does have
government buildings and a post office. Another village, Slaterville
Springs, has no government but does have a special tax assessment.
New york state has nearly 20 different types of local government
(what Freebase would call a /location/citytown.) Every point in New
York, including the great wilderness of the Adirondacks, is part of a
municipality (4th level administrative subdivision), but there are
places in New Mexico that are unincorporated and that only belong to a
county (3rd level administrative subdivision.)
Perhaps the U.S. is a more difficult case than most other
countries because a :U.S._State has a high degree of autonomy.
Medicaid, our program that provides health care for the indigent is
administered by individual states, and supported by taxes that I pay to
my County. In most U.S. States I can buy a bottle of wine at the
supermarket, but in New York I have to go to a liquor store and not on
Sunday, except for the one liquor store in town that (inexplicably) is
open on Sunday. Don't forget that the U.S. also has non-:State
components such as DC, Puerto Rico, and Guam.
In other countries, a "2nd level administrative division" means
something very different.
Since there are another 200 or so countries "1st level
administrative divisions" in the world (nobody is sure about the exact
right number) the problem is way worse than that.
In geonames, there are "Nth level administrative divisions"
where N=1...4, and maybe if you let N go to 5 or 6 sometimes, you're
doing about as well as can be done for the world.
Now you might think :City isn't so bad but that's not the case.
:Los_Angeles is a :City that is inside a :County. :New_York_City is
really a :City (4th level) but is has five counties (3rd level) inside
of it. :London and :Tokyo (which everyone expects to be on the top-10
:City list) aren't even cities, they are administrative subdivisions
that contain cities... And there's no clear distinction between a
:Village, :Town, and :City, any more than there is between a :Hill and
a :Mountain.
Now, it's a fair complaint that the extraction system behind
DBpedia is less than perfect, but I think the ontology behind it is
correctly designed and detailed for the job it has to do.
"Vernacularizing" it so that :Tokyo is a :City and "specializing" it so
it knows everything about administrative divisions in Indonesia are
interesting enrichment projects, but what it aims to do right now is
about as useful as is practical.
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