[Talk-us] New I.D Feature

Toby Murray toby.murray at gmail.com
Sat Nov 8 08:05:44 UTC 2014


On Sat, Nov 8, 2014 at 12:35 AM, Greg Morgan <dr.kludge.gm at gmail.com> wrote:
>
>
> It is unfortunate that importers are dropping values like addr:city and
> addr:state during US imports.  Especially when they appear to have clean
> data at the time of import.  There are other users of the OSM data than
> just Nominatim.  I imagine that our data looks crappy to a person wanting
> addresses without the concerns or abilities of GIS applications.
>
>
To be clear, addr:city *IS* being used on imports and is useful
information. Postal addresses for cities often extend far beyond the
physical city boundaries and therefore can not be inferred by use of
boundary relations. This is not the case with state and country which means
the information in these tags is duplicated data.

4.) Though not confirmed by me, it feels like to me that European addr:city
> values actually mean a city boundary.  I am guessing Nominatim prefers
> addr:city over is_in tags because of my perceived idea that European
> addr:city values more closely match the actual jurisdiction geometric
> area.  What does addr:city in the US mean then?  The jurisdiction of the
> POI or the postal value for the POI?
>

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.


Toby
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