[mkgmap-dev] Problem in AngleFixer?

Sat Aug 10 17:38:19 BST 2024

Hi Thorsten

Let me know if the road_speed and/or road_class are different with the style you
are using. If they are all the same I don't understand why it should give a turn
instruction.

If it is just the road_speed, I'll do another patch that prioritises road_class,
then "likely same road", then road_speed.

Ticker

On Sat, 2024-08-10 at 16:27 +0100, Ticker Berkin wrote:
> Hi Thorsten
> 
> The algorithm, in choosing which arc headings to adjust to remove sharp turns,
> prefers to adjust lower class roads. If class is the same it adjusts lower
> speed
> road. If these are the same, with my change it, it sees if one is reasonably
> straight and adjusts the other. As a last resort it adjusts both.
> 
> This, I consider, is reasonable and gives good results almost all the time.
> 
> With the default style both ways have speed=1 class=0 and so it adjusts way
> 144732811. However if your style gives them different classes/speeds
> (144732811
> is paved, the other is unpaved) it will bend way 36138336 such that this might
> trigger a right-turn instruction if going from south to north.
> 
> I'm not sure what the best solution is for your example.
> 
> Regards
> Ticker
> 
> On Sat, 2024-08-10 at 10:01 +0200, Thorsten Kukuk wrote:
> > Am 2024-08-10 09:39, schrieb Thorsten Kukuk:
> > 
> > > To get that right: Your patch fixes one half of my first example: if 
> > > you let Garmin calculate the route, it will now use the junction and 
> > > will not use u-turns and detours to avoid it. So your patch is an 
> > > improvement.
> > > What it does not fix is the wrong navigation instruction: it tells you 
> > > to turn right if you need to go straight forward, and if you need to 
> > > turn left it doesn't tell you anything. And this shouldn't have 
> > > anything to do with road speed or surface.
> > 
> > Maybe pictures explain it better:
> > 
> > 1. routing-no-patch.png is vanilla mkgmap r4921, Garmin makes two 
> > forbidden u-turns and a detour and avoids the junction.
> > 2. routing-with-patch.png is mkgrmap r4921 with your patch, Garmin uses 
> > the junction.
> > 3. navigation-instruction-turn-right.png: at the junction with a route 
> > straight forward Garmin Software and Devices tell you to turn right in 
> > navigation mode.
> > 
> > I hope this explains it better.
> > 
> > Regards,
> > Thorsten
> > 
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