Do not render type=route relations

[cquest]

When a type=route relation with matching tags exists (like railway=* or highway=*) the rendering takes place twice. This may cause tunnels to be re-rendered as non tunnels.
I've fixed it with success in OSM-FR tiles.

[matthijsmelissen]

Thank you, I will look at it.

[cquest]

Example: missing tunnel (hidden by the line from the route relation)

http://tile.openstreetmap.fr/?zoom=16&lat=48.97634&lon=2.99525&layers=B0000000FFFFFF (osmfr)
http://tile.openstreetmap.fr/?zoom=16&lat=48.97634&lon=2.99525&layers=B0000000FFFFFF (osm.org)

[gravitystorm]

Good catch. But is this a bug in osm2pgsql relation handling? It's not obvious why you would need to add these "and route is null" to every sql statement in the first place.

[cquest]

That's not really an osm2pgsql bug. It depends on the style used by osm2pgsql (is it keeping route=* relations or not) and OSM data (is there some tags on the route relation that could be the same as other object rendered).

Another way to avoid the rendering bug could be the same as with polygons... order by decreasing length forcing mapnik to render small pieces on top of long ones, but this implies have a length column like we have an area column on polygons.

[pnorman]

but this implies have a length column like we have an area column on polygons

Well you could order by st_length(way), but that'd probably send performance down; although you could add a btree index on st_length(way), and it could sort by that without evaluating the function.

Either way, it doesn't exactly sound like a great option.

The problem with a length column is that it's meaningless in a way, because osm2pgsql splits long ways.

[matkoniecz]

railway=* or highway=* in relations - is it a correct tagging?

[Theodin]

Does this collide with #596 ? In my opinion routes should be tagged as relations (individual roads can have different names) and tagging them as ref on a way is just tagging for the renderer.

[pnorman]

railway=* or highway=* in relations - is it a correct tagging?

No.

I'm thinking to close this as it sounds like a tagging error

[matkoniecz]

I would propose to close it as a tagging error, I see no reason to use this kind of tagging and I found no recommendations to do this on wiki.