[OSRM-talk] Directions related to bifurcations and ramps

Anders Gunnarsson anders.gunnarsson at appello.com
Mon Oct 6 15:14:03 UTC 2014


Hi,

I'm quite new to OSRM and this mailing list, so please point me in the right direction if these subjects has already been covered.


There seems to be a lot of misleading turn instructions related to bifurcations, ramps and similar. You may get an instruction to turn in the opposite direction than what you need to do to stay on the route, or you may not get an instruction at all. Below there are some examples.
In the last example you also get a misleading turn slight right instruction, when you should merge onto the motorway after passing through the junction. This is also fairly common and could be a problem if there was a ramp right after the junction
I read somewhere that angles and street name changes are used to generate turn instructions. That would explain a lot of the issues.

Are there any open issues related to this or should I create any new? Are there any thoughts on what a solution would look like?



Examples:
Turn right to go on ramp missing, turn left where there is no junction when renamed to Högsboleden instead
http://map.project-osrm.org/?hl=en&loc=57.664928,11.937027&loc=57.675228,11.934548&z=14&center=57.668245,11.906991&alt=0&df=0&re=0&ly=763558683


Bifurcation with two lanes in each direction. You need to stay in the two leftmost to stay on route. I would prefer an instruction to keep left or turn slight left.
http://map.project-osrm.org/?hl=en&loc=57.699093,11.995164&loc=57.683273,12.005291&z=14&center=57.683574,11.960464&alt=0&df=0&re=0&ly=763558683

The same bifurcation but where you need to keep in the two rightmost. I would prefer keep left or turn slight left instead of continue onto 40;27
http://map.project-osrm.org/?hl=en&loc=57.698643,11.995078&loc=57.682781,12.016500&z=16&center=57.692302,11.993513&alt=0&df=0&re=0&ly=763558683


Here the instruction to continue onto Åbromotet is not saying anything since the entire junction is Åbromotet. Instead of that you need an instruction to keep right or turn slight right. The instruction to turn slight left is not needed, unless you're in a rally car, since you don't have an option to go elsewhere.  
http://map.project-osrm.org/?hl=en&loc=57.643372,12.005609&loc=57.682781,12.016500&z=16&center=57.645356,12.010684&alt=0&df=0&re=0&ly=763558683

The same junction when going to south. Here you get an instruction to turn slight right when you need to keep left or turn slight left.
http://map.project-osrm.org/?hl=en&loc=57.643372,12.005609&loc=57.640079,12.028263&z=16&center=57.643970,12.020067&alt=0&df=0&re=0&ly=763558683

Best regards,
Anders






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