[OSRM-talk] Keep left and keep left and ...

[Brad Colbert]

Thank you Flo,

This makes sense.  Luckily I'm not too concerned about the turn-by-turn
results but this made me question the route.  I think it looks ok so maybe
I put this on the back shelf and revisit later.

Again, thank you.
-B

On Sat, May 8, 2021 at 7:46 AM Florian Lohoff <f at zz.de> wrote:

> On Fri, May 07, 2021 at 09:36:34AM -0700, Brad Colbert via OSRM-talk wrote:
> > Hello Everyone,
> >
> > I'm working on modifying a profile.  Now when I run, the turn-by-turn
> has a
> > ton of "Keep left at the fork" lines and I'm wondering why and how/if I
> can
> > get rid of them.
>
> Whenever you get announcements like this its unclear junctions e.g.
> the angle of the roads split is the problem. You get an announcement
> whenever the angle is greater than a certain default.
>
> Most of the time its the OSM Data which needs fixing.
>
> A couple years back i made a quick drawing to make the point:
>
> https://silicon-verl.de/home/flo/tmp/osm-spitzer-winkel.jpg
>
> On the left you see a typical OSM junction - When traveling
> left to right you may hear a "keep left" on the left junction because
> the angle is so great.
>
> In reality junction are layed out like the one on the right. And
> following the center line your angle is in most cases roughly 90° which
> will cause no announcement when traveling across.
>
> Announcements like this are caused by geometry or topology.
>
> Flo
> --
> Florian Lohoff                                                     f at zz.de
>   Any sufficiently advanced technology is indistinguishable from magic.
>
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