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

Sat Jan 31 21:05:26 GMT 2009

Gert Münzel escribió:
> Carlos Dávila schrieb:
>>> 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. 
Checking the map in gpsmapedit I realized that although I split the
problematic road in several small pieces in JOSM, they are again merged
in a single one when I create the mp file using osm2mp. I would like to
split the road in the mp map to test again, but I don't find any tool
for that in gpsmapedit.
>> 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
>>
>
> Hi, Carlos,
>
> actually i don't us roundabouts i my trailmap. I have a full routable
> version of this map created with cgpsmapper. The database is the same
> mp-file.
> I guess not the count of pieces is important but there seems to be a
> max for length and/or cout of nodes.
> Also i guess it's more a coincidence that you observe the problem
> starting with a roundabout.
> I guess it's more like, if there are any polylines in any place of a
> calculated route, doesn't matter which type of polyline, which ar to
> long, you get in trouble with this route.
>
> Regarding the tagging of areas, i'm sorry but yet i don't know
> anything about osm-format. I think if the the data is in
> correctmp-formam the results with mkgmap and cgpsmapper should be the
> same, and as i already mention my map compiled with cgpsmapper
> definitly works fine.
> Also i use only a few small polygons for areas, which are not crossed
> by the route.
> Ok, anyway maybe there are more then one reason for this problem.
>
> cheers Gert