[mkgmap-dev] Virtual paths

Tue Jul 28 23:33:04 BST 2020

ael <witwall3 at disroot.org> writes:

>> 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?

I didn't say your idea made no sense.  I said that I didn't expect the
discussion to go well :-)  But don't let my guess stop you.

I prefer soemthing like a polygon of type highway=path that covers the
free-routable space, to which regular ways are connected to.  Sort of
the same thing, but without adding relations in, and treating
free-routable areas as first-class items similar to line-routable ways.

> 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.

My impression is that people synthesize a bunch of diagonals when there
is an erea, for routers that don't do areas.