2011/2/22 Tamas Janovics <[email protected]>: > Hello! > > I use Mapnik with openlayers and postgis database. I have an osm map from > hungary and another hungary map in the postgis/postgresql database. > When I visualize the maps in my browser i get the following maps/pictures. > See below: > Hungary OSM map: http://img14.imageshack.us/img14/4318/hungaryosm.png > My other Hungary map: http://img7.imageshack.us/img7/2817/hungaryroad.png > > My problem is that the projection isn't good enough, because Hungary is > "thicker" or "higher". My map (not the osm map) is in WGS84 projection, and > I use this in my mapfile: > > <Map srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"> > ... > <Layer srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"> > > I think that the view center of my map is by the 0.0 (lat) and 0.0 (lon) > coordinates, that's why my maps are "thinner" than on other maps. > Is that really my problem? What should i change in my settings?
AFAIK the system you use (EPSG 4326) creates the effect to "squash" the map in respect to the real angles. Spherical Mercator (900913) which is used by OSM maintains the angles (but has the problem of area sizes being distorted the more you move towards the poles). I recommend you use another projection (if you don't like spherical Mercator you might have a look what your local mapping agency uses, generally they tend to use a projection which is nice for the area they are covering ...). cheers, Martin _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
