[OSM-dev] Fwd: [OSM-newbies] Reverse geo coding

Thomas Wood grand.edgemaster at gmail.com
Thu May 28 13:48:38 BST 2009


Forwarding this to OSM dev from newbies.


---------- Forwarded message ----------
From: Michael Handerek <osm at handerek.net>
Date: 2009/5/28
Subject: [OSM-newbies] Reverse geo coding
To: "newbies at openstreetmap.org" <newbies at openstreetmap.org>


Hi,

I am new to osm. I am currently developing a prototype of a reverse geo
coding tool based on a local osm db. The input has to be a
latitude/longitude pair and the output a human readable address.

I already handled it to extract the street name and postal code of a
lat/long pair using the tags of a nearest-neighbor-node. To do this with
a acceptable query time i use the k-nearest-neighbor algorithm
(http://www.bostongis.com/?content_name=postgis_nearest_neighbor_generic#130).

Now I have to get at least the country and city name. In order to do
this i see two possibilities.

1. Searching for the nearest city node, in order to extract the
information from his tags.

2. Creating geometries for each continent, country and city in order to
check if nodes are within.

May someone know some better method to get the needed information, feel
free to discuss.


The 1. possibility, also used by 'Where are they'
(http://wiki.openstreetmap.org/wiki/Where_Are_They), for me, seems to be
imprecise.


Regards,
Mic

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-- 
Regards,
Thomas Wood
(Edgemaster)




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