2010/7/16 Marko Mäkelä <marko.makela@iki.fi>:
Have you tried splitting the tiles further? In my experience, mkgmap does not always flag errors when exceeding some Garmin limits, and you can end up with all sorts of breakage (including routing errors in some areas) when you generate too large tiles. The OSM data set has a tendency to grow. A year ago, 2 or 3 tiles of Finland was enough. Now I am splitting it to 6 tiles.
...just found the Problem: My build Process (for a multi-layer map) includes setting the main layer (roads, POI) to transparent using gmt.exe because mkgmap somehow doesn't manage to make this singe layer transparent. gmt.exe seems to kill the road-searching information in this layer's gmapsupp.img. When I then compile all gmapsupp.img files into one with mkgmap, its not included... Did someone else also experience this transparency problem? Maybe we'll have some more elegant way of creating multi-layered maps with mkgmap at some point in the future. -Martin