Reinhold, I just ran through your test script and confirmed that I get nice output for all the projections listed with Mapnik2 (trunk)
However, the script needs to use mapnik.ProjTransform to handle forwarding the bbox that is used, otherwise a bogus bbox can be sent to mapnik (and of course that would lead to a blank map). I tested with an osm stylesheet referencing data imported into postgres in spherical mercator projection. Fixed up script is here: https://gist.github.com/1098240 Dane On Jul 21, 2011, at 1:10 PM, Dane Springmeyer wrote: > Reinhold, > > Artem and I just connected on this via skype. We have some fixes for this > issue in Mapnik2 (current trunk) and are *not* planning on backporting them > to 0.7.x. > > Are you able to upgrade to the development version of Mapnik? > > Dane > > On Jul 21, 2011, at 7:52 AM, Reinhold Klatt wrote: > >> >> ------ Forwarded Message >> From: Reinhold Klatt <[email protected]> >> Date: Thu, 21 Jul 2011 14:41:22 +0200 >> To: Artem Pavlenko <[email protected]> >> Conversation: [Mapnik-users] Mapnik and conic projectionsP >> Subject: Re: [Mapnik-users] Mapnik and conic projectionsP >> >> Hi Artem, >> >> I'm using the version 0.7.1 from mapnik.org >> >> Reinhold >> >> >> On 21.07.2011 14:23 Uhr, "Artem Pavlenko" <[email protected]> wrote: >> >>> Which version of Mapnik are you using? >>> Artem >>> >>> On 21 July 2011 11:42, Reinhold Klatt <[email protected]> wrote: >>>> Hi all, >>>> I'm trying to render maps in a conic projection. The problem is, that i get >>>> a blank image as result. >>>> If I generate in mercator or latlon there is no problem. I get what I >>>> want. >>>> But I can't generate anything in a conical projection. >>>> I modified a script I found, to test different projections. Does anybody >>>> know why it's not working? What's my mistake? Are there parameters that >>>> have >>>> to be set? >>>> >>>> Thankyou in advance >>>> >>>> >>>> #!/usr/bin/python >>>> import mapnik >>>> >>>> mapfile = "style9_nodem.xml" >>>> >>>> projections = { >>>> "latlon": "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs", #EPSG:4326 >>>> "google": "+proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +a=6378137 >>>> +b=6378137 +units=m +no_defs", # SR-ORG:95 >>>> "mercator_world": "+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 >>>> +datum=WGS84 +units=m +no_defs", # SR-ORG:16 >>>> "lambert": "+proj=lcc +lat_1=49.83333333333334 +lat_2=51.16666666666666 >>>> +lat_0=90 +lon_0=0 +x_0=150000 +y_0=5400000 +ellps=intl +pm=brussels >>>> +units=m +no_defs", >>>> "albert": "+proj=aea +lat_1=29.83333333333334 +lat_2=45.83333333333334 >>>> +lat_0=37.5 +lon_0=-96 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m >>>> +no_defs", >>>> "pytest": "+proj=lcc +lat_1=45.89893890000052 +lat_2=47.69601440000037 >>>> +lat_0=46.8 +lon_0=2.33722917 +x_0=600000 +y_0=200000 +a=6378249.145 >>>> +b=6356514.96582849 +pm=2.337229167 +units=m +no_defs", >>>> } >>>> >>>> ll = (8.487, 49.9857, 8.6237, 50.0622) >>>> >>>> imgx = 1000 >>>> imgy = 1000 >>>> >>>> # Render an image for every projection >>>> for projName, projDef in sorted(projections.items()): >>>> >>>> print "Projection: " + projName >>>> >>>> # Load the map data >>>> m = mapnik.Map(imgx, imgy) >>>> mapnik.load_map(m, mapfile) >>>> >>>> # Override projection defined in osm.xml >>>> m.srs = projDef >>>> >>>> # Calculate projected boundaries >>>> prj = mapnik.Projection(projDef) >>>> c0 = prj.forward(mapnik.Coord(ll[0], ll[1])) >>>> c1 = prj.forward(mapnik.Coord(ll[2], ll[3])) >>>> >>>> # Apply bounding box >>>> bbox = mapnik.Envelope(c0.x, c0.y, c1.x, c1.y) >>>> m.zoom_to_box(bbox) >>>> >>>> # Render image >>>> im = mapnik.Image(imgx, imgy) >>>> mapnik.render(m, im) >>>> view = im.view(0, 0, imgx, imgy) >>>> view.save("img/" + projName + ".png", "png256") >>>> >>>> >>>> _______________________________________________ >>>> Mapnik-users mailing list >>>> [email protected] >>>> https://lists.berlios.de/mailman/listinfo/mapnik-users >>>> >>> >> >> ------ End of Forwarded Message >> >> >> _______________________________________________ >> Mapnik-users mailing list >> [email protected] >> https://lists.berlios.de/mailman/listinfo/mapnik-users > _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
