[mkgmap-dev] Problem in AngleFixer?

Sat Aug 10 16:27:33 BST 2024

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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