[OSM-dev] osm2pgsql on Freemap: Mapnik rendering not working

Nick Whitelegg nick at hogweed.org
Sat Oct 20 14:01:50 BST 2007

Hello Jon,

> You got my address wrong.

Sorry, for some reason  I thought you were uklinux.net. :-)

> > http://www.free-map.org.uk/stuff/osmmerc.xml

> 150MB is a big to download to verify the data co-ordinates. Can you try
> something like the following it should tell you whether you have latlong
> co-ordinates or not:
> gis=> select name,astext(way) from planet_osm_point where name='London';
>   name  |                  astext
> --------+-------------------------------------------
>  London | POINT(-14236.7498650935 6678032.76431355)
>  London | POINT(13770176.7059706 1462100.03299675)

As far as I am aware the coordinates have always been in Mercator; I have just 
verified this by asking for London and I get the first one (take it the 
second one is London, Ontario)

> The above shows the co-ordinates in my DB are Mercator which would
> notwork with your osmmerc.xml file.

> If you want to work with mercator co-ords then change all the postgis
> layers in your osmmerc.xml to specifiy:
>   srs="+proj=merc +datum=WGS84  +k=1.0 +units=m +over +no_defs"

OK this seems to work, thanks :-) What *is* odd, though, was that the old 
definitions, which specified latlong, *did* work with my osmmerc.xml file 
before, whilst if I had them all as merc/WGS-84, they did not. Remember 
having immense difficulty with this back in March. Anyway, all appears to be 
working now :-)


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