[mkgmap-dev] mkgmap-869 pinky routing line

Wed Feb 11 14:18:09 GMT 2009

On Feb 11, 2009, at 13:51, Gert Münzel wrote:
> Yes, r877 seems to fix it. Actually i only tested it with the simple  
> track i sent, but i will test it with more complicated networks of  
> trails.
>
> Just for my interest (actually i don't no much about the structure  
> of Garmin imgs and what is hold in the NET NOD RGN etc. sections),  
> but how it is possible that one trackpart, which looks ok to me,  
> causes this problem?

It was a bug in mkgmap:

A rounding error in the distance calculation between two nodes in the  
track caused a floating point result of NaN (not a number) instead of  
zero, because for the particular latitude involved, it turned out that  
sin(lat)^2+cos(lat)^2 was greater than 1. The NaN in turn was  
apparently converted to the integer 0, and written to the IMG as such  
(in two places: the length of the road in NET, and the length of the  
edge in the routing graph in NOD).

Cheers
Robert