[OSM-dev] What about sharing basic rendering rules and using SLD?

[Andy Allan]

2008/6/2 Stefan Keller <sfkeller at gmail.com>:

> P.S. What I'm missing in most rule definitions from Mapnik, Osmarender and
> Kosmos (as far as I know them) is that there is no rendering priority,
> right? With that one could control explicitly e.g. the rendering of parking
> whih overlap railway station symbols.

There is a rendering priority for all of them.

Mapnik operates on a painters model, which means objects are drawn one
at a time. The order that objects are returned from the db for each
layer, the order of the layers in the osm.xml file, and the order that
each object is compared against the rendering rules in each style are
all important (although the last one is rarely used since each feature
generally only matches one filter to prevent brain-exploding
complexity).

So, as a cartographer, I can say "I want all station symbols drawn at
the expense of parking symbols" and control that through the rendering
rules, by putting the station symbols first.

Cheers,
Andy