[Talk-us] New I.D Feature

Sarah Hoffmann lonvia at denofr.de
Sat Nov 8 20:11:37 UTC 2014


Hi,

On Sat, Nov 08, 2014 at 02:05:44AM -0600, Toby Murray wrote:
> Nominatim actually does not correctly use addr:city. You are correct in
> that it does assume a better match between physical border and postal city
> address. What happens is it actually puts city information on *roads* based
> on boundary relations and place=* nodes. Then it links individual address
> points to the roads. The addr:city tags on POIs and building outlines is
> actually completely ignored. This leads to things like this address not
> being found if you search for it in Manhattan, KS:
> https://www.openstreetmap.org/node/2209430502
> 
> On the other hand, this one on the next street over is found because I
> added an addr:city tag to the road:
> https://www.openstreetmap.org/node/2209427353
> road:
> https://www.openstreetmap.org/way/13226787
> 
> I consider this to be a nominatim bug and haven't attempted to do a mass
> tagging of roads with addr:city because I see this as essentially tagging
> for the renderer.

Well, agreed that Nominatim still misses the feature to mix in addr:* tags.
It is somewhere on the todo list. To be honest, I'm not very motivated to
fix it for the sake of US postal towns because I'm not yet convinced that
the addr:city tag is the right solution for that concept.

Postal towns are by all technical means areas and you should really consider
tagging them as such. Let me just outline why addr:city is difficult from
a point of view of searching. Assume Nominatim would handle addr:city
correctly. That would alow you to find '6001 Stony Brook Drive, Manhattan'.
But what about 'Stone Brook Drive, Manhattan'. I expect you would want
to be able to find that too? That would only work if you added addr:city
to the road as well or Nominatim added some means to infer from the addresses
that the road is postal code-wise in Manhattan. It gets even more difficult
for the addresses that have not yet been mapped. If there are addr:city
tags on addresses in other streets nearby, then some dark magic might still
guess the expected postal town correctly but it still means you need to 
add some addresses first. Any tagging schema that implies that much guessing
really should be reconsidered.

Postal towns is really a concept that wasn't taken into account when the
Karlsruhe address schema was developped and IMHO doesn't really fit. I'd
really like to see some discussion in the US community about how it can
be tagged including considering the possibility to come up with a brand
new way of tagging it. If you then come to the conclusion that addr:city
is still the best way to go, so be it. But I'd be far more happy to
support something in Nominatim that fits exactly the US situation than
hack some European tagging system until it hopefully gives the right
result most of the time.

Kind regards

Sarah
(your friendly nominatim maintainer)





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