Mapnik tiles have latitude distortion, projection issue?

Question

I'm trying to work out a kink in setting up mapnik-node.

My geos are in postgis, and I allllmost have them rendering properly, but my GIS experience is lacking so I can't seem to determine why this isn't working correctly.

Here's an example overlayed on a map. I'm getting a weird distortion on the latitude but not on the longitude. http://cl.ly/image/0K3i1x3n2L3v

I can provide a snippet of the mapnik code, if that helps. But hoping this is just a simple bug—some kind of projection issue that I'm not seeing.

My polys are stored in the db with srid=4326. The bounding box I calculate for the tile x/y/z matches perfectly with what should work.

Answer 1

Figured it out.

I needed to add in:

map.aspect_fix_mode = mapnik.Map.ASPECT_RESPECT;

before:

map.extent = bbox;