Public Transport rendering
The very useful OePNV map has not updated in recent months, and it seems a real shame not to be able to make similar renders to this. There were also a few things which I missed on OePNV map: long distance bus routes rendered at lower zoom levels, stop area groups also. A bit of idle chit chat on IRC caused me to look at some of these issues. These are just notes of work in progress.
These are shown in OePNV as a translucent yellow area, with rounded corners. The basic PostGIS to generate these polygons for bus stops as nodes is : ST_BUFFER(ST_CONVEXHULL(ST_COLLECT(n.geom)),10) .
Basically very easy, can follow the existing layer-ferry-route.xml.inc in the default Mapnik 0.7 install & modify for buses.
Bus Route numbers
Not so easy, particularly from the osm2pgsql install which loses the relationship between this data & the way. A performant way to get it back requires availability of the relation_members table, and full tags on the osm2pgsql tables. There are various additional performance options to be explored too.
Types of Bus Routes
More exploration needed.