[mkgmap-dev] Bug in Road Merging - actually doubling roads.

Tue Mar 20 19:44:13 GMT 2018

Yes it only happens on device.  Simulating routing via:
http://www.openstreetmap.org/browse/way/310376420 will in this case not
switch off the device, but just get stuck. Map moving forward/backwards
slightly.
Here you could reproduce it by simply doubling the routable lines - one
routable line for highway=path, another one for the relation route=hiking
or route=mtb. 6 Routable lines (which are not oneway) with exactly the same
way on top of each other are enough to reliably cause the Oregon 600 to
break routing in my experience.

The arc list actually helped me to identify some common problems in my
style so I could reduce some routable lines - but in my experience adding
several lines on top of each other - with different road_class/road_speed
helps prioritise those ways. For highways this is not needed - as they are
straight. But with mountain pathes - often a road_class 4, road_speed 2 is
already too high importance to be chosen for curvy pathes, so adding a
road_class 3, road_speed 1, and road_class 1, road_speed 0 will help to
prioritize such ways. Also adding relations as routable lines often helps
in so far that at least according to gpsmapedit they have much less
routable nodes than the underlying way - so maybe that helps prioritizing
them too?

Felix

On 20 March 2018 at 17:30, Gerd Petermann <gpetermann_muenchen at hotmail.com>
wrote:

> Hi Felix,
>
> well, up to now I thought that you want to fix the problem in your style
> and just need help to find out where it happens.
> I still don't understand why your style adds so many routable lines, in my
> eyes this is an errpr on your side.
> But you may be right, mkgmap might be able to change the bearing values of
> an arc when there are too many equal ones.
> You never told me what exactly I should do to reproduce a problem. In
> previous posts you wrote about crashes, now you
> mention broken routing. I guess this still only happens on the device?
>
> Gerd
>
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von
> Felix Hartmann <extremecarver at gmail.com>
> Gesendet: Dienstag, 20. März 2018 13:23:37
> An: Development list for mkgmap
> Betreff: Re: [mkgmap-dev] Bug in Road Merging - actually doubling roads.
>
> well I think if ways are overlapping which have identical nodes it should
> be possible to throw away according to say this prinicple:
> a) identical tags (except name which is not important) - throw away the
> copy/copies. I think here it is clear the copies are not needed.
> b) identical tags (except name) plus more tags.
> Eg way 1 has: key1=a key2=b     way 2 has key1=a, key2=b key3=c. So throw
> away way1.
> If there is however
> way 1 has: key1=a key2=b  key3=c    way 2 has key1=a, key2=b key4=d. it is
> more complicated but it could still be merged to a single way consisting of
> key1=a, key2=b, key3=c, key4=d
> if
> way 1 has: key1=a key2=b  key3=c    way 2 has key1=a, key2=b key3=d we
> could keep both ways, or throw away one of them - but yeah then it is not
> clear which one so better keep.
>
>
> For the problems related to  http://www.openstreetmap.org/
> browse/way/310376420
> and the other 2 ways. Following a) removes one copy. Following rule b)
> would actually get rid of the second copy and now information/detail will
> be lost.
>
>
> I'll try the new patch and see if I can find out more about problems.
>
>
> BTW - would it not be better to just use a test map for finding the error?
> I'm pretty sure any 6 routable roads on top of each other (identical
> direction) cause routing to break on Oregon 600. As soon as some way is
> slightly different angle - it is fine.
>
>
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>

-- 
Felix Hartman - Openmtbmap.org & VeloMap.org
Schusterbergweg 32/8
6020 Innsbruck
Austria - Österreich
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.mkgmap.org.uk/pipermail/mkgmap-dev/attachments/20180320/7dff3012/attachment.html>