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[mkgmap-dev] gpx track files do not work on routable maps

From Eric Fernandez zeb at zebulon.org.uk on Wed Mar 7 14:33:19 GMT 2012

2012/3/7 Marko Mäkelä <marko.makela at iki.fi>:
> On Wed, Mar 07, 2012 at 11:15:33AM +0000, Eric Fernandez wrote:
>>The routing almost work perfectly (using cycleways) until the very last
>>end: at around N55 degrees 27.922' / W003 degrees 39.085' then the
>>navigation jumps in a straight line to the end (going through
>>fields/unmarked areas).
> That one does ring a bell. If you disable or remove the gmapsupp.img
> (Settings/Map, uncheck the box, or remove or rename the file), do you
> see a way on the base map (gmapbmap.img) where the straight line is?

No, there is an empty field on the basemap when it breaks navigation.
If I recalculate using the basemap only, then the straight line starts
a bit before.
Note that my lock on road option is "off". Is that a problem?

> Or,
> if you rename the gmapbmap.img to something else, do you get a 'route
> calculation error' instead of the straight line?

Now that is interesting ! Without a basemap at all, but using the the
OSM/gmapsupp.img map, then navigation is a lot better! Indeed there
are still some glitches and break lines (unconnected junctions?), but
not as dramatic as before. bh_road3.gpx is still broken (Begin and End
overlap) but for many other longer ways, the navigation is a lot more
accurate and go through GPX track points. I still spotted broken
lines, but they were vary rare now. This might suggest some kid of
interference betwen the stock Garmin basemap and the OSM map generated
with OSM.

Could it be a kind of priority between the maps? I am aware of
--draw-priority, but this is for drawing only, isn't it? It is
strange, it is as if the Edge were using both the mapsource and the
basemap to calculate navigation, instead of relying on the most
detailed map!!

Besides, can you tell me what the version of your basemap on your Edge 705 is?

Also, would it be possible to create a very simplified basemap from
OSM for the Garmin? Maybe that would prevent this issue by having more
consistency? But really the Edge should ignore the basemap entireley
when a mapsource is available!

> One possible explanation is that there is an unconnected junction (two
> fully or almost overlapping nodes in the junction, or missing connection
> in a T junction) or that there is a highway=pedestrian area that is not
> being translated as a routeable way, but only as a polygon.

Possible, but the problem occured on all GPX files I tried with our
without cycleways, including very short junctions (bh_road3.gpx) for

I have another idea: is it possible to make all roads equivalent in
the style file? Just to see how navigation works? I suppose this is
stated in the "lines" file?

> Have you tried different routing options? Instead of bicycling, try car
> (shortest route). Then it should ignore any cycleways or plazas that
> might be broken in the OSM data.

Well the problem looks similar, but it might be because I used
--ignore-turn-restrictions --ignore-maxspeeds in my options. This
might mess up the car setting? I'll try again without them.

> I should have a little more time in a week or two.

Thank you very much. Do not hesitate to contact me in case you want me
to do further testing.

Kind regards,

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