should not fork slight left when road goes straight

[emiltin]

osrm emits a fork left instruction when the way continues straight ahead (same bearing before/after).

it should probably suppress the instruction (if the forking road is minor) or tell you to go straight at the fork.

situation:

response:

{
  "waypoints": [{
    "location": [12.620201, 55.661265],
    "hint": "HgsAgP___38zBAAAhgAAAPIAAAAAAAAAAAAAAMs9AAAQaQAAVwcAAKmRwADRUlEDqJHAANZSUQMAAAYGwiCf8g==",
    "name": "Øresundsvej"
  }, {
    "location": [12.6194, 55.661196],
    "hint": "fzMAgP___38zBAAAxAAAAAYBAAAAAAAAAAAAAA9pAAAKZQAAVwcAAIiOwACMUlEDiI7AAJBSUQMAAAYGwiCf8g==",
    "name": "Øresundsvej"
  }],
  "routes": [{
    "distance": 50.8,
    "duration": 30.4,
    "legs": [{
      "distance": 50.8,
      "steps": [{
        "distance": 18,
        "duration": 10.8,
        "name": "Øresundsvej",
        "maneuver": {
          "type": "depart",
          "location": [12.620201, 55.661265],
          "bearing_before": 0,
          "bearing_after": 261
        },
        "geometry": "}ivrIg{_lADv@",
        "mode": "pushing bike",
        "intersections": [{
          "location": [12.620201, 55.661265],
          "bearings": [261],
          "entry": [true],
          "out": 0
        }]
      }, {
        "distance": 32.9,
        "duration": 19.6,
        "name": "Øresundsvej",
        "maneuver": {
          "type": "fork",
          "modifier": "slight left",
          "bearing_before": 261,
          "bearing_after": 261,
          "location": [12.619918, 55.661241]
        },
        "geometry": "wivrIoy_lAFfB",
        "mode": "pushing bike",
        "intersections": [{
          "location": [12.619918, 55.661241],
          "bearings": [75, 255, 300],
          "entry": [false, true, true],
          "in": 0,
          "out": 1
        }]
      }, {
        "distance": 0,
        "duration": 0,
        "name": "Øresundsvej",
        "maneuver": {
          "type": "arrive",
          "location": [12.619918, 55.661241],
          "bearing_before": 261,
          "bearing_after": 0
        },
        "geometry": "oivrIgv_lA",
        "mode": "pushing bike",
        "intersections": [{
          "location": [12.6194, 55.661196],
          "bearings": [81],
          "entry": [true],
          "in": 0
        }]
      }],
      "duration": 30.4,
      "summary": "Øresundsvej"
    }],
    "geometry": "}ivrIg{_lADv@FfB"
  }],
  "code": "Ok"
}

using latest from master

[MoKob]

Usually forks are analysed for major/minor roads. So far guidance work is targeted at roads only. The addition of the footpath here introduces an unknown priority of roads that is obviously not handled correctly, yet.

This is related to #2113 and is already on the list.

[emiltin]

ok

[MoKob]

Just a heads up. The work on guidance decisions in profiles already provides improvements:

[emiltin]

nice!

[emiltin]

looking at the updated profile i see there's a new function setClassification(highway, result). i'm not sure exactly how this works, but having only the highway tag is probably not going to be enough since routability depends on a number of tags. for example, a highway=runway IS routable if you have car=yes or bicycle=yes.

i'm also wondering about the two directions. for bikes, a way can have different modes for each direction (cycling, pushing_bike) - won't this affect classification/guidance?

[MoKob]

@emiltin the setClassification is a default way of how you may choose to handle stuff. You have the possibility to ignore roads (may_be_ignored flag) and you can set road-categories from a set of types.

Since guidance is changing quite a lot at the moment, its kind of hard to describe the implications of different flags/categories. You can have a look at the lib (lib/guidance.lua) to see what is currently set.
For bicycles, you probably want to provide a own way of setting the values using the additional information you mentioned.

Edit: Regarding the two different modes - this is definitely correct and we will have to update our behaviour here at some point. The first goal at this point is to reproduce our current behaviour with the possibility to offer configuration at profile level, not at compile level.
Next steps will have to include additions like different classifications for different directions.

[MoKob]

@emiltin I've added some (minor) documentation on the configuration in my PR. Keep in mind that these configurations most likely will have to change when we focus on improving bicycle and walking guidance.
The configuration should already help in improving our responses for cyclist, but (just like you mentioned) some features are still necessary to further improve guidance for non-car navigation.

[emiltin]

alright, thanks

[MoKob]

With #2586 reviewed and waiting on merge, this issue is resolved (at merge, of course).