Hi all, I've installed and got mapnik working for shape, tab and postgis and am making good progress...but I have a question regarding projections :
My shape file is in WGS84. I reference a particulare area of the world file in standard lat/long notation in the python script eg: bbox = mapnik.Envelope(mapnik.Coord(-180.0, -75.0), mapnik.Coord(180.0, 90.0)) What I was wondering is that if I change the projection of the python script/XML styles to EPSG: 3857 (Popular Visualizations) and the shape file remains in WGS84 is that going to cause a conflict in terms of which projection is used? The reason I ask is that I altered the projection to: srs="+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs" and then altered the Envelope clause to bbox = mapnik.Envelope(mapnik.Coord(-2022737, 476045), mapnik.Coord(3223267, 5458042)) (focussing on Spain) but no joy - I get a white png image and no errors which makes be think it's just taken a snapshot of nothing since lat/long isn't in this range. So either I cannot override the shape file projection, or I am doing it incorrectly...is this possible Many thanx, BC
_______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
