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

Fri May 29 13:15:00 BST 2009

I think these penalties are in general usefull for routing optimization. 
On an normal 90° crossing they will be 30 sec on a 50 km/h street, which 
seems quite reasonable for me for car routing. This helps the routing 
algorithm to prefer straight lines without a lot of street changes.

I'm astonished by the values.
357 sec are 6 minutes!

I have tried to interpret your values and observations:
Seems to me, that the penalty gets calculated by a formula similar to 
((180°/x)-1)*3.3*roadSpeed.

So these values are extreme values because of the extreme situation. An 
15° corner on an highway is really not usual...
(and I think it would need 6 minutes to sort out the traffic :-)

Regards,
Johann

Marco Certelli schrieb:
> 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:
>
>   
>