[OSM-dev] Rendering Route Relations with Mapnik

[Jon Burgess]

On Sun, 2011-07-17 at 09:05 +0100, Graham Jones wrote:
> John,
> Thanks for the explanation - I saw the ferries route styles in the OSM
> mapnik style, but wasn't sure if this was plotting relations or just
> ways tagged with 'route'.
> 
> 
> So, if I want the route details, I should be able to search for items
> in the planet_osm_line table with negative IDs and 'route=hiking',
> then look up the route information in the planet_osm_rels table using
> that ID.....I'll give it a try.

It should not be necessary to query the rels table. If you add the keys
that you want from the hiking relation into the default.style then this
information should be copied into new columns in the line table. 

One thing to be aware of is that the name= tag on the relation becomes
route_name in the database. This allows both the way and relation names
to be present simultaneously. There are also some other special
conversions related to some cycle network tags, see
http://trac.openstreetmap.org/browser/applications/utils/export/osm2pgsql/output-pgsql.c#L879

   Jon