One correction:
in 2. I ment standard deviation instead of standard mean.
WanMil
Hi,
I remember that it is on my Todo-List :-)
So I performed a quick implementation following your suggestion. You can
find in the attached patch so that you can play a little bit with it.
(Attention: it is completely untested!!)
You can find a patched mkgmap.jar at http://files.mkgmap.org.uk/detail/215.
I think curviness should to be defined in a different way.
1. Calculate the distance of each point Dmiddle to the virtual line from
first to the last point.
2. curviness()=standard mean(Dmiddle/(length to next point + length to
previous point)
I think this gives a better indication how curviness a road is. But it
need to be implemented and tested later on :-)
WanMil
Hi all,
Garmin offers "curvy roads" preferences for their zümo 390 and 590
devices.
https://buy.garmin.com/en-US/US/on-the-road/motorcycles/zumo-390lm/prod138275.html
I'm thinking about creating motorcycle maps for old 200 series.
Might it be useful to integrate a curviness() function so that mkgmap
can optimize for curvy roads too? It might also help do determine a
better default speed for curvy roads for use with car routing.
The curviness() value might be the overall absolute turning angle (in
degrees) of a road segment divided by the segment's length.
What's your opinion?
Cheers
Manfred
Pseudo code might look like this:
function curviness()
{
oldpoint=points(0)
foreach (point of a way segment as newpoint)
{
d_x=(newpoint.x-oldpoint.x)/360*40000000*COS(newpoint.x*PI()/180)
//in meters
d_y=(newpoint.y-oldpoint.y)/360*40000000 //in meters
length+=sqrt(d_x**2+d_y**2)
angle=arctan(d_y/d_x)
d_angle=abs(angle-old_angle)
sgn_x=sgn(d_x)
sgn_y=sgn(d_y)
if ((sgn_x*sgn_y*old_sgn_x*old_sgn_y)=-1 && (sgn_x!=old_sgn_x))
d_angle=pi-d_angle // 180 degrees correction, otherwise north-south
roads show strange results
if (point>1) sum_angle+=d_angle
old_angle=angle
oldpoint=newpoint
old_sgn_x=sgn_x
old_sgn_y=sgn_y
}
return sum_angle/length
}
// perhaps simple multiplication is faster than 4 times sgn() functions?
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