[mkgmap-dev] Problem with --adjust-turn-headings

Thu Feb 11 17:27:40 GMT 2010

Hi Mark,

> 
> Some Garmin GPS units can tell you which lane to be in (lane
> assist?) but we don't know how to encode that info. Pity, as that's just
> what you need here.

I know this would be cool but I expect only something simple. attached is gpx with 2 routes for a situation where motorway_link  divides into 2 with similar angle and same name, class …
this is a very common situation and Roadtrip creates a keep left/right instruction. have tested only one of them with my Etrex and will test the other one today.  In the other case where one route continues on same name,ref,class this keep left/right instruction is omitted. I think in case of different road class we should omit turn instructions but in case of same class it should be done. especially on multi lane highways it's better to have one or to redundant instructions.
An automatic default will be great but also some manual route relation or tag is an option. a tag on the junction node like force_turn_instruction could be used.
If this is possible I will use the through-route only where it's absolutely needed.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: route.GPX
Type: application/octet-stream
Size: 4799 bytes
Desc: not available
Url : http://lists.mkgmap.org.uk/pipermail/mkgmap-dev/attachments/20100211/a37d55c9/attachment.obj 
-------------- next part --------------

> 
> But looking at the sat pic, I would think that adding a through_route
> relation is reasonable because more of the road lanes continue on
> to the I-80 BUS than they do to the I-80.
> 
> Ah, a subtle point here is that it will probably tell you to turn right
> rather than keep right at the junction. But I can probably fix that by
> making mkgmap notice that all of the roads are motorways and so reduce
> the amount of heading change. But in the meantime, if you want to add
> that relation (and you will need my patch to mkgmap, of course) and
> test what happens, it will be interesting to know.
> 
>> 
>> And again there is a navi failing this test. Google navi on Android doesn't announce a keep right instruction and I bet 50% who rely on their navi will miss the right turn.
> 
> Very likely, so we should be able to do better than that!
> 
> Cheers,
> 
> Mark
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev