On Tue, Jul 28, 2020 at 08:46:02AM -0400, Greg Troxel wrote:
ael <witwall3@disroot.org> writes:
Not just mkgmap. It is a general problem. Maybe OSM should introduce a new relation "connected"? That is one or more ways and/or points could be members implying that it is possible to navigate (perhaps directly) between any of them. That would solve many of the problems for all routers. This idea needs expansion: a tag on the relation would specify the mode of transport, although I guess this would be mainly foot. Likewise, some sort of seasonal tag would be useful. But most of those already exist for ways, so I suppose those could be just be applied to the relation as well.
Right now we represent this with ways, and they have well-defined semantics. This seems comlicated and would need implementation in many data consumers.
Just musing out loud. If it seems sensible, maybe a proposal on the tagging list?
Feel free; I don't expect that to go well.
As far as I can see, the current discussion is just a special case of a general problem with OSM. Consider a park with grass cover with open access, or even just an area of, say open access moorland where it is possible & sensible to walk anywhere. As far as I know, all the OSM routers will fail to construct a route across such a place (presumably a straight line) in the absence of an explicit way of some sort. Adding a relation of the sort I suggested which would be verifiable and objective would solve the problem. Is there a better solution? Of course, routers would not pick this up immmediately. As for mkgmap, I see that the Garmin firmware probably needs to support it somehow. Are we sure that Garmin doesn't have something that can interpolate between routing points? I guess that navit could probably be extended to do this sort of thing. ael