[mkgmap-dev] rendering nested relations

Fri Dec 7 14:08:49 GMT 2012

I'm struggling to render nested networks of international cycling route relations and maybe found an issue with the sort order of relation ID's.
My observation is that if the parent relation has a higher ID than the child relation, my mkgmap style won't render the tags of the parent relation on the underlying ways.

For example, this cycleway which is part of a (super)relation EV12 (North Sea Cycle route) and a national route LF1.

http://www.openstreetmap.org/browse/way/4549529 (cycleway)
http://cycling.waymarkedtrails.org/nl/?zoom=17&lat=52.13921&lon=4.33606

	part of Noordzeeroute (2761)
	network = ncn, ref = LF1, route = bicycle, type = route
	http://www.openstreetmap.org/browse/relation/2761

			part of North Sea Cycle Route - part The Netherlands (1977662)
			network = icn, ref = EV12, route = bicycle, type = superroute
			http://www.openstreetmap.org/browse/relation/1977662

				part of North Sea Cycle Route (1207220)
				network = icn, ref = EV12, route = bicycle, type = superroute
				http://www.openstreetmap.org/browse/relation/1207220

My goal is to get ref EV12(North Sea Cycle Route) on this cycleway, but all it gets are the ncn tags LF1 (Noordzeeroute).

With a similar route relation in Germany, I don't have problems to render it, for instance this way:

http://www.openstreetmap.org/browse/way/23018057 (highway=secondary)
http://cycling.waymarkedtrails.org/nl/?zoom=15&lat=52.0506&lon=6.70903

	part of D3 D-Netz-Route (Nordrhein-Westfalen) (2003425)
	network = ncn, ref D3,  route = bicycle, type = route
	http://www.openstreetmap.org/browse/relation/2003425

		part of Capitals Route (2003423) 
		network = icn, ref EV2, route = bicycle, type = superroute
		http://www.openstreetmap.org/browse/relation/2003423

		part of	D-Netz-Route 3 (901472)
		network = ncn, ref D3,  route = bicycle, type = route

With this way, mkgmap renders tags EV12 (Capital route) as expected.

With JOSM I found out that the sort order of the relation ID is the problem. 
If I swapped the contents and tags of relation 2761 and 1977662 (of course I didnt upload it to OSM, just saved the file) it gets rendered.
If I make a new relation, it gets a negative ID and there is no problem either, all the relations that I put in this new relation gets the tags from the parent relation.

In the German route example, the parent relation has a lower ID than the child, 2003423 vs 2003425. With this the relation styles have no problem to render it.

Is there a way to solve this?