R: [mkgmap-dev] Maps not for Cars and sharp-turns, U-Turns

Fri May 29 08:35:40 BST 2009

Interesting experiments, thank you!

Maybe, we should add these results to the Wiki?
http://wiki.openstreetmap.org/wiki/Mkgmap/routing

Is there any chance to get influence on these penalty values? I.e., is there a penalty factor included in gmapsupp.img file which can be adjusted?
OK, this would be a search for the needle in a haystack...

Markus

-------- Original-Nachricht --------
> Datum: Thu, 28 May 2009 23:03:19 +0000 (GMT)
> Von: Marco Certelli <marco_certelli at yahoo.it>
> An: f.hartmann at fh-krems.eu, Development list for mkgmap <mkgmap-dev at lists.mkgmap.org.uk>
> Betreff: R: [mkgmap-dev] Maps not for Cars and sharp-turns, U-Turns

> 
> Made some test.
> 
> during fastest route serching, garmin gives a time penalty to turns. time
> penalty seems propotional to road speed so I think it just calculates a
> speed reduction due to turn and then a linear increase of speed up to the road
> speed.
> 
> for a steep 15° turn I got 357 second penalty on a motorway (road_speed=6
> i.e 108km/h) and 237 second penalty on a primary (road_speed=4 i.e.
> 72km/h)
> 
> as the angle widens, the penalty is reduced (at 45° is about 1/3 the
> above values, at 90° about 1/8)
> 
> Ciao, Marco.
> 
> 
> --- Gio 28/5/09, Felix Hartmann <extremecarver at googlemail.com> ha scritto:
> 
> > Da: Felix Hartmann <extremecarver at googlemail.com>
> > Oggetto: [mkgmap-dev] Maps not for Cars and sharp-turns, U-Turns
> > A: "Development list for mkgmap" <mkgmap-dev at lists.mkgmap.org.uk>
> > Data: Giovedì 28 maggio 2009, 23:17
> > After playing around a bit with maps
> > and getting really confused why on some ways I could not
> > route along with car/motorcycle setting, even though all
> > access restrictions were sorted out, I found out that in
> > case of very low angle of roads meeting, in car/motorcycle
> > setting huge detours maybe made just to turn around.
> > 
> > This is quite impractical as the best routing performance
> > can be achieved with the car/motorcycle setting when writing
> > the maps in such a way that bicycle use is assumed to be
> > used as car/motorcycle. Using a bicycle there is no need to
> > prohibit any kind of u-turn, but I think we can't get this
> > out of the garmin programming but by changing the data
> > source. Has anyone any idea how we could sort out this
> > problem with preprocessing?
> > 
> > Actually this might be usefull for car/motorcycle uses as
> > well. It would be better to rely on turn-restrictions than
> > on the garmin GPS simply deciding that at some place turning
> > is impossible and making a detour to turn! I don't know the
> > angle but I think if the meeting angle is lower than
> > somewhere around 20° this happens. So roads meeting would
> > need to be changed to meet at bigger angles than 20°. To
> > really find out the angle upon which Garmin GPS/Mapsource
> > decide a car can't turn (note avoid U-turn is not activated
> > of course) would need some test maps however.
> > 
> > _______________________________________________
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> > mkgmap-dev at lists.mkgmap.org.uk
> > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> > 
> 
> 
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