I'm trying to use mapnik to render a Robinson projection centered in the pacific ocean (example [1]). However, I've run into some issues trying to get a correct rendering.
I started off with the tm_world_borders shapefile [2], and re-projected it into the robinson projection with ogr2ogr: ogr2ogr -t_srs '+proj=robin +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs +over' robin_world_borders.shp tm_world_bounders.shp Using the following script: http://pastebin.com/f7f3b0784 -- I get a partially correct rendering [3], due to the known issue of antarctica (although I'm not sure why it doesn't work), so I removed antarctica using the following ogr2ogr command: ogr2ogr -sql "select * from robin_world_borders where Name <> 'Antarctica'" robin_sans_antarctica.shp robin_world_borders.shp Using this file, I can now get a correct rendering with a greenwich center (sans Antarctica, of course), however I cannot get a correct rendering centered on the dateline. I tried the following: 1. Specify lon_0=180 on the map's projection, as shown here: http://pastebin.com/fc2f26a5 This only shows the eastern hemisphere: http://i42.tinypic.com/16h1e6h.png (shows western only if I use lon_0=-180) 2. Reproject the shapefile using ogr2ogr: ogr2ogr -t_srs '+proj=robin +lon_0=180 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs +over' robin_sans_antarctica.shp robin_sans_antarctica_shifted.shp This produces a stranger result, where countries that span the prime meridian are all drawn incorrectly: http://i41.tinypic.com/12542o4.png (code used: http://pastebin.com/f59e42e0c ) Any tips on where I've gone wrong here? Also, if anyone knows hows to render Antarctica in the Robinson projection that'd be great as well :) Thanks! filipe [1] http://commons.wikimedia.org/wiki/File:BlankMap-World-162E.svg [2] http://thematicmapping.org/downloads/world_borders.php [3] http://i40.tinypic.com/2e4m8f5.png
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