[OSM-dev] Mapnik style broken?

Martijn van Oosterhout kleptog at gmail.com
Tue May 15 10:26:41 BST 2007


On 5/14/07, Artem Pavlenko <artem at mapnik.org> wrote:
> As I mentioed in another email, I think the layering model of mapnik is
> currently slightly different to other renderers. I think Mapnik always
> draw lines over the top of areas even if the area has a higher layer set
> than the line. This is because it renders all polygons, then lines, then
> points, then text / symbols (at least this is what I understand, perhaps
> Artem can confirm or correct me).
>
> At the moment, yes polys->lines->points. But we can change this by storing
> mixed geometries (as used to be:)
> in one big table and using global z_ordering. It will work but we need well
> defined rules for how to order features.

It seems to me you don't ever want areas to be drawn over roads. Even
in the case of a tunnel, you draw the area first and then the road as
a dotted outline. It's still drawn after. Drawing areas later just
obliterates anything underneath (unless you have alpha blending, but I
didn't think so).

Have a nice day,
-- 
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/




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