[mkgmap-dev] LocationHook and tagging ways

Tue Jan 10 21:25:29 GMT 2012

> Hi list,
>
> as discussed before, the current implementation of LocationHook produces
> somehow unpredictable results when it locates ways that cross boundaries.
> A correct solution would be to split the way, but according to WanMil this
> would be very slow.

I think so. But of course it would be good to try that. Maybe it's also 
possible to differ between a quick mode (the one which is implemented) 
and an exact mode (splitting ways and shapes at the boundaries).

> So, with bad luck, we may find a way with 100 points in a boundary that
> contains only one of them.
>
> While thinking about a test for my optimized version I wondered why we put
> all points of a way into the quadtree, and not only one (e.g. the 1st, the
> last, or the one in the middle).
> Using only one point makes the quadtree much smaller and faster, and the
> result is (almost) as correct as before.
> I see only one problem: If the way crosses boundaries, one of the boundaries
> may contain better information (more complete) than the other(s). If we
> chose the "wrong" point for searching, we may find only the incomplete
> information.

That's the problem. In areas where boundaries are not 100% complete a 
lot of elements are not assigned.

WanMil

>
> Gerd
>
>
>
>
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