[mapserver-users] Mapserver, OpenStreetMap and hstore - great new possibilities

[Rahkonen Jukka]

Hi,
 
For those playing with OpenStreetMap data: it is worth knowing that it
is now possible to import all the tags that exists in the OpenStreetMap
data into PostGIS.  New version of osm2pgsql has an option to import
just everything into PosgreSQL column of type hstore. I do not know what
it is actually but it behaves like a garden shed and collects all the
junk that exists, with the difference that from hstore it is also
possible to find something.
 
I had a try by importing some OSM data into PostGIS and making a
Mapserver layer that queries the hstore column.  LAYER DATA is something
like this:
DATA "way from (select (way),osm_id,tags from osm_point where (tags
@>'amenity=>cafe')) as foo using unique osm_id using srid=2393"
 
This layer shows now all the points which have amenity=cafe tag in the
OSM data.  Layer can also be make to dynamic one by using variables
DATA "way from (select (way),osm_id,tags from osm_point where (tags
@>'%tag%=>%value%')) as foo using unique osm_id using srid=2393"
 
By adding &tag=something&value=somevalue into WMS GetMap request I can
show on a map just enything that I want from OSM data.  And
GetFeatureInfo can show all the tags of the queried feature, see a QGis
example at http://wiki.openstreetmap.org/wiki/User_talk:JRA
 
-Jukka Rahkonen-
 
 


 
 
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