[mkgmap-dev] Wrong_route_calculation / strange straight routing lines on GPS

Thu Jan 29 13:35:25 GMT 2009

>On Jan 28, 2009, at 23:10, Gert Münzel wrote:
>/> making my first steps with mkgmap that, although the routing works  
/>/> fine in Mapsource, i get in trouble on my Gps unit Garmin gmap60csx.  
/>/> Very often i got these strange straight magenta routing lines in  
/>/> between normal routing.
/>/> Meanwhile i figured out that it seems to be that t has something to  
/>/> do with the length of a polyline. I don't know if it is the count of  
/>/> points/nodes of the polyline or still the lenght or both.
/>/> But comparing the same mp-file once compiled with mkgmap, once with  
/>/> cgpsmapper i see, that cgpsmapper split these long lines during  
/>/> mkgmap leave them like they are.
/>
>How did you compare the IMG files? Have you tried decompiling the  
>broken IMG with test.display.*? Have you tried manually splitting the  
>polylines in the .mp-file? Does it help?
>
>My guess is that the problem lies with long polylines (in the .mp- 
>file) that are split into several polylines (in the IMG) by mkgmap,  
>which results in a road made up of several polylines.
>
>But if I understand you correctly, maybe the problem is just with long  
>polylines in the IMG file?

I think there must be something else than length of polylines and number 
of nodes. I get this error in a route that always starts at a node in a 
roundabout, no matter how far you fix the destination out of this point 
or in how many pieces you split the way. In another case, error seems 
to me to be related with the route crossing boundaries of an area 
tagged as area=yes, landuse=industrial, place_name=Pol. Ind. Las 
Capellanías