Re: [OSRM-talk] Snapping preferences

[Daniel Patterson]

Hi François,

  Currently, no - snapping for coordinates is strictly whichever is nearest
(with one exception:
https://blog.mapbox.com/robust-navigation-with-smart-nearest-neighbor-search-dbc1f6218be8
).

  I can think of two things:

1.  Try using the `/match` API.  This API snaps to *many* nearest
points (usually within 15m), and tries routes between all combinations, and
returns the most likely.  As long as your coordinates are reasonably close
(<2km), it should be almost usable as a replacement for the `/route` API.

2.  You can use the `/nearest` API to return more than one possible
snap point within range, then pick one, then request `/route` with the
snapped coordinates you have chosen.  This is only viable if `/nearest`
returns enough information for you to decide which snapping point is best.

daniel


On Fri, May 4, 2018 at 8:37 AM, François Lacombe 
wrote:

> Hi all,
>
> I'm wondering if osrm can weight its snapping choices for start location ?
> Especially for footwalk mode.
>
> There are situations where farer ways can lead to shorter routes.
> Currently osrm always snap start location to nearest way but doesn't give
> me the shortest route according to my knowledge.
>
> Is there any trick in the profile to make some ways preferable to snap to?
> Should I open an issue regarding this?
>
> All the best
>
> *François Lacombe*
>
> fl dot infosreseaux At gmail dot com
> www.infos-reseaux.com
> @InfosReseaux 
>
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[OSRM-talk] Weird behaviour of Turn-restriction in OSRM

[Xavier Prudent]

Dear all,

This is my first project with OSRM and OSM.

I experience a very troubling behaviour of the turn restriction with osrm.

I edit an osm map and want to remove any possible u-turn or left turn.

If you look at this map, and look for the point #22

https://civiliagroupeconseil-my.sharepoint.com/:u:/g/personal/xprudent_civilia_ca/EXFdH132gY1Pk38xz54uN08BL87-xayY1WC7jLMTP9axHQ?e=UkCpL6

I give you here a zoom on the Rue Perras. You can see a u-turn is done on
this street by osrm

https://civiliagroupeconseil-my.sharepoint.com/:i:/g/personal/xprudent_civilia_ca/ETEmfFrTyIdGrWPwALg-jNMBLhFNB78b068x8ceNRqOw5g?e=YA8dOT

But the rue Perras in the JOSM editor forbids left turns, as shown here

https://civiliagroupeconseil-my.sharepoint.com/:u:/g/personal/xprudent_civilia_ca/Ef2rIh5MZ1VNnxrLxcTUkwgB1lJ0d_rTPcfBTH94I3BzCg?e=pd09Va

and adding u-turns don't change anything. That is troubling as this
procedure works on many intersections, but not for a couple of others ?!?

Here is the OSM map I edit

https://civiliagroupeconseil-my.sharepoint.com/:u:/g/personal/xprudent_civilia_ca/Ef2rIh5MZ1VNnxrLxcTUkwgB1lJ0d_rTPcfBTH94I3BzCg?e=StlweD

Being a newbie, I must have overlooked something important.

Thanks in advance,

Regards,

Xavier
-- 

*Xavier Prudent *

*Data Scientist  - Data Mining - Machine Learning*

Web:* www.xavierprudent.com *
Tel (Québec)  : (514) 668 76 46
Skype : xavierprudent
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