[OSM-talk] 2 divided carriage-ways meeting at traffic lights.

[Dave Stubbs]

On Wed, Mar 19, 2008 at 10:52 AM, Steve Chilton <S.L.Chilton at mdx.ac.uk> wrote:
> <snip>
>
> PS. Why are trunk_links rendered above primary/secondary streets. It
>  make
>  ugly junctions.
>
>  This has bothered me for a while now but I have not got round to fixing
>  it. It does look ugly and I think is quite easily fixed. At the moment
>  rendering of mway/primary/trunk and their respective foo_link variants
>  is dealt with by the same lines of code in the mapnik style. The answer
>  is probably to separate the foo_link instances out to a separate layer
>  and stack it to draw BEFORE all other major road instances. It is on my
>  list of TODOs but the number of instances of code to change involved
>  (diff renders for mway, primary, trunk per zoom scale, plus all the
>  bridge and tunnel variants) has always put me off actually doing it so
>  far.
>

It might be better to tweak the z-ordering in the osm2pgsql import for
this, otherwise the layer tag is just going to get ignored. Currently
link roads are assumed to be in the same z-order as the main type.
It's the first column in this structure:
http://trac.openstreetmap.org/browser/applications/utils/export/osm2pgsql/output-pgsql.c#L96