[Geocoding] Bbox option on Nominatim

[Sarah Hoffmann]

Hi,

On Wed, Jan 15, 2014 at 03:31:04PM +0100, Rodolphe Quiédeville wrote:
> So if I write here it's because I maintain a nominatim serveur for
> geocoding on a bbox that covers Europe, so I loaded it with an export
> from geofabrik (thanks to them) and now run hourly update on it. If I
> well understood, the update process load worlwide datas in the database,
> so I propose to add an option --bbox to Nominatim to filter the
> changes. The option will have the same structure as osm2pgsql and the
> value will be set on osm2pgsql command line using it's option '-b'.
> 
> Before doing the patch, I wanted to discuss it about you, what do you
> think about and have you some hints ?

There is no general objection to adding such a parameter but you should
be aware that the bbox option in osm2pgsql might actually do less than what 
you want. It only filters node objects, ways and relations are still imported
completely. Most of the time, this will do what you want because without
nodes outside the bbox, the geometry for the ways and relations cannot be
computed and without a geometry, the objects should not appear in the
Nominatim tables. However, osm2pgsql's slim tables will still grow with
the unnecessary data.

If daily updates are sufficient for you, you should try Geofabrik's
daily diffs[1]. They work well with Nominatim and will avoid the 
problem of bloated tables. The setup is described in the installation
instructions.

Sarah

[1] http://download.geofabrik.de/europe-updates/



> 
> Best regards,
> 
> PS : I've already found the Github repo of Nominatim and done a first PR
> on the munin plugin nominatim_importlag, my nick on github is 'rodo'.
> 
> -- 
> Rodolphe Quiédeville
> Expert Tsung - Consulting en performance des SI
> Tel : 06 13 79 63 41
> http://blog.rodolphe.quiedeville.org
> 
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