[OSM-dev] Nominatim geocoding for Japanese address

Sarah Hoffmann lonvia at denofr.de
Wed Apr 9 22:55:44 UTC 2014

On Wed, Apr 09, 2014 at 02:23:54PM -0700, Troy Wu wrote:
> On Apr 9, 2014, at 11:23 AM, Sarah Hoffmann wrote:
> > On Wed, Apr 09, 2014 at 12:52:49AM +0900, Satoshi IIDA wrote:
> >>> Japanese address system
> >> I made Japanese address structure for OSM, last year.
> >> And got consensus between Japanese mappers. also reported in Tagging ML.
> >> https://lists.openstreetmap.org/pipermail/tagging/2013-September/014816.html
> > 
> > I rememeber this mail but obviously misunderstood that it is an
> > finished proposal. I also cannot find much data that follows the schema.
> > Taginfo reports that there are more addr:block_number than addr:blocknumber
> > but that might be unrelated.
> And then what about other countries?  In Taiwan, there's the idea of main road, alley/subroad, then building identifier.  I'm sure other places will have different address formats.  Someone just mentioned that the best solution is to create a geocoder for each "type" of address?  Is that the trajectory of geocoding for OSM?  To have a per-country/region based geocoder?

I sincerily hope not.

The reason that geocoding works so badly outside Europe is first of
all a data problem. The only systematic addressing proposal we have
to date is the Karlsruhe schema and that was indeed developed with
European street addressing in mind. There is no use in developing
a localized geocoder until the tagging problem for other addressing
schemas is sorted out.

So if your country addressing doesn't work, by all means, propose
extensions to the current addressing schema that solve your problem.
You should discuss these things in your local community first, then
document it in the wiki and put it out on tagging@ for discussion
to find out if maybe other countries have a similar problem which
can be solved at the same time. And please, open a trac ticket
for Nominatim to let the developers know why addressing in your
country does not work and what you are planning to tag.

Of course, there is no gurantee if/when things get actually implemented
because there are simply too few developers to implement the stuff.
Again, writing a new geocoder won't really help with that problem.
It would be much better if the few people interested in this topic
would join forces and manage to work on one common project.

> And, someone mentioned that Nominatim isn't good in the US?  I'm trying to implement some basic geocoding (all US addresses), and that would be somewhat devastating.  Is this actually the case, before I spend time going down this path?

I'm looking at this from another continent, so I might be wrong,
but the problems with geocoding in the US look mostly like a data
problem as well. Boundary data in particular is really bad in the US.
The good news is that the US community has worked hard on improving
the data in the last year and I'm quite confident that these things
will get sorted out soon. There are also some particularities with
US addressing where the tagging still needs to be defined better (i.e.
postal towns) but apart from that I don't think Nominatim would do
that badly.

There is also now the address repository that Ian Deeds announced a
few days ago. This data could be mixed into Nominatim as external
data quite easily and further improve the rather patchy house number

If all that in its current state is enough for your needs, I don't
know. You should run a trail with a small set of data on the
publicly available instances to find out.


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