[OSM-dev] Hstore revolution

Jukka Rahkonen jukka.rahkonen at latuviitta.fi
Wed May 19 14:29:24 BST 2010

Sven Geggus <lists <at> fuchsschwanzdomain.de> writes:

> As far as Database queries are concerned one should use something
> like this for performance reasons:
> select ... from planet_osm_point where (tags @> 'amenity=>fire_station');
> rather than
> select ... from planet_osm_point where (tags->'amenity' = 'fire_station');
> Which is quite slow.

I tried to use the way you suggested with Mapserver run time substitution system
but I was not able to resolve the correct way for quoting some characters.
However, I did succeed with the latter query. It means that if Mapserver
administrator allows, the users can create dynamic WMS layers with any possible
tag=value combination just as they like. And if Mapserver administrator allows,
users can even deside what styles (color, line width etc.) they want to use. Like
- show all points with FIXME as red dots
- show all highway=residential and maxspeed=40 as blue line

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