[Navigation] Unnecessary SlightTurn directions in some situations

AntonM030481 commented

2022-03-18 09:04:32 +00:00

(Migrated from github.com)

For some reason I have notification 'Keep left' here, moving by main road to cross-road.
Take a note that this is Cyprus (left-side driving).
In fact a lot such kind of notifications can be heard.
Maybe this is somehow related to the fact that most of roads in Cyprus are not straight.

https://omaps.app/4yxfvno7P6/Strovolou_Avenue
om://4yxfvno7P6/Strovolou_Avenue

For some reason I have notification 'Keep left' here, moving by main road to cross-road. Take a note that this is Cyprus (left-side driving). In fact a lot such kind of notifications can be heard. Maybe this is somehow related to the fact that most of roads in Cyprus are not straight. <img width="414" alt="image" src="https://user-images.githubusercontent.com/85622715/158972165-7ec4fd46-cbb3-4bd8-ab24-cc58f41f600e.png"> https://omaps.app/4yxfvno7P6/Strovolou_Avenue om://4yxfvno7P6/Strovolou_Avenue

CorruptComputer commented

2022-03-18 14:51:53 +00:00

(Migrated from github.com)

I think this is a duplicate of #2238

AntonM030481 commented

2022-03-18 16:49:08 +00:00

(Migrated from github.com)

Agree. Very similar one. Route: https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=35.14404%2C33.34396%3B35.14498%2C33.34465

AntonM030481 commented

2022-03-18 17:23:25 +00:00

(Migrated from github.com)

My suggestion is to not voice if:
all roads except 1 deviate more then (90 - alpha) degrees from current direction
and 1 road deviates less then (alpha) degrees from current direction

if there is 1 main road road we increase alpha trying to follow main road.
E.g. for alpha = 10

2 equal roads angles:
5, 85 - no voice.
5, 75! - voice
15!, 85 - voice

2 roads. first primary. alpha increase to 20 trying to follow main road
15, 75 - no voice
25!, 75 - voice
15, 65! - voice
75!, 5 - voice
85, 15! - voice

Edit:
Voice = directions

My suggestion is to not voice if: all roads except 1 deviate more then (90 - alpha) degrees from current direction and 1 road deviates less then (alpha) degrees from current direction if there is 1 main road road we increase alpha trying to follow main road. E.g. for alpha = 10 2 equal roads angles: 5, 85 - no voice. 5, 75! - voice 15!, 85 - voice 2 roads. first primary. alpha increase to 20 trying to follow main road 15, 75 - no voice 25!, 75 - voice 15, 65! - voice 75!, 5 - voice 85, 15! - voice Edit: Voice = directions

biodranik commented

2022-03-20 22:45:03 +00:00

(Migrated from github.com)

The problem is not in the voice but in the underlying directions. There are some unnecessary directions inserted by the algorithm. More examples where other routers don't have unnecessary turns, but OM has them, will be helpful.

Announcing a turn on the main road with clearly visible secondary roads is completely unnecessary, right? If there are no directions, then it means "continue forward on the current road", right?

The problem is not in the voice but in the underlying directions. There are some unnecessary directions inserted by the algorithm. More examples where other routers don't have unnecessary turns, but OM has them, will be helpful. Announcing a turn on the main road with clearly visible secondary roads is completely unnecessary, right? If there are no directions, then it means "continue forward on the current road", right?

👍 1

AntonM030481 commented

2022-03-21 20:15:20 +00:00

(Migrated from github.com)

Exactly!

AntonM030481 commented

2022-03-24 12:05:58 +00:00

(Migrated from github.com)

Is it correct that white arrows - directions points? If so it's I can easily provide a lot of examples.

From:
https://omaps.app/0yxfvyMryq/ΚΑΠΕΚΛΟΠΟΙΕΙΟΝ_ΦΥΛΑΚΤΟΥ
To:
https://omaps.app/0yxfvwODtI/Longou

Is it correct that white arrows - directions points? If so it's I can easily provide a lot of examples. ![image](https://user-images.githubusercontent.com/85622715/159912060-da61b6ae-109a-4486-9e4f-b917254c6e82.jpeg) From: https://omaps.app/0yxfvyMryq/ΚΑΠΕΚΛΟΠΟΙΕΙΟΝ_ΦΥΛΑΚΤΟΥ To: https://omaps.app/0yxfvwODtI/Longou

AntonM030481 commented

2022-03-24 12:29:47 +00:00

(Migrated from github.com)

Another example:

From:
https://omaps.app/0yxfvN4NFs/
To:
https://omaps.app/0yxfvllmin/

Another example: ![image](https://user-images.githubusercontent.com/85622715/159916410-4b81d58f-2c17-4eb9-a797-0874d402ba85.jpeg) From: https://omaps.app/0yxfvN4NFs/ To: https://omaps.app/0yxfvllmin/

biodranik commented

2022-03-24 19:50:25 +00:00

(Migrated from github.com)

Is it correct that white arrows - directions points? If so it's I can easily provide a lot of examples.

Correct, thanks!

> Is it correct that white arrows - directions points? If so it's I can easily provide a lot of examples. Correct, thanks!

👍 1

AntonM030481 commented

2022-03-24 22:48:22 +00:00

(Migrated from github.com)

Can you explain current algorithm of determination of directions?
Looks like it is now:

for all intersections:
 if abs(path change angle) > alpha:
  direction = true
 else:
  direction = false

Can you explain current algorithm of determination of directions? Looks like it is now: ``` for all intersections: if abs(path change angle) > alpha: direction = true else: direction = false ```

AntonM030481 commented

2022-04-13 17:20:30 +00:00

(Migrated from github.com)

I checked the code for function GetTurnDirection.
It uses the function KeepTurnByHighwayClass
I have created function KeepTurnByAlignedAlternatives using the same design and tested it. It fixed most of issues for me.

/// * \returns true when
/// * - any alternative turn to bigger road
/// * - or any alternative turn to similar road if turns less then 70 degress (wider than SlightTurn)
/// * - or any alternative turn to smaller road if turns less than SlightTurn
/// * Returns false otherwise.
/// \param possibleTurns is all possible ways out from a junction.
/// \param turnInfo is information about ingoing and outgoing segments of the route.
bool KeepTurnByAlignedAlternatives(TurnCandidates const & possibleTurns, TurnInfo const & turnInfo,
                           NumMwmIds const & numMwmIds)
{
  // Note. The bigger road the less HighwayClass value.
  ftypes::HighwayClass outgoingRouteRoadClass = turnInfo.m_outgoing.m_highwayClass;

  // The turn should be kept if there's no any information about feature id of outgoing segment
  // just to be on the safe side. It may happen in case of outgoing segment is a finish segment.
  Segment firstOutgoingSegment;
  if (!turnInfo.m_outgoing.m_segmentRange.GetFirstSegment(numMwmIds, firstOutgoingSegment))
    return true;

  Segment inversedLastIngoingSegment;
  if (!turnInfo.m_ingoing.m_segmentRange.GetLastSegment(numMwmIds, inversedLastIngoingSegment))
    return true;
  inversedLastIngoingSegment.Inverse();

  for (auto const & t : possibleTurns.candidates)
  {
    // Let's consider all outgoing segments except for
    // (1) route outgoing segment
    // (2) a U-turn segment (inversedLastIngoingSegment)
    if (t.m_segment == firstOutgoingSegment || t.m_segment == inversedLastIngoingSegment)
      continue;
    ftypes::HighwayClass const highwayClass = t.m_highwayClass;
    // Note. The bigger road the less HighwayClass value.
    if (static_cast<int>(highwayClass) < static_cast<int>(outgoingRouteRoadClass))
    {
      // any alternative turn to bigger road causes keep turn
      return true;
    }
    else if (static_cast<int>(highwayClass) == static_cast<int>(outgoingRouteRoadClass))
    {
      // any alternative turn to similar road causes keep turn if turns less then 70 degress (wider than SlightTurn)
      if (fabs(t.m_angle) < 70)
        return true;
    }
    else
    {
      // any alternative turn to smaller road causes keep turn if turns less than SlightTurn
      if (IsGoStraightOrSlightTurn(IntermediateDirection(t.m_angle)))
        return true;
    }
  }
  return false;
}

I checked the code for function **GetTurnDirection**. It uses the function **KeepTurnByHighwayClass** I have created function **KeepTurnByAlignedAlternatives** using the same design and tested it. It fixed most of issues for me. ``` /// * \returns true when /// * - any alternative turn to bigger road /// * - or any alternative turn to similar road if turns less then 70 degress (wider than SlightTurn) /// * - or any alternative turn to smaller road if turns less than SlightTurn /// * Returns false otherwise. /// \param possibleTurns is all possible ways out from a junction. /// \param turnInfo is information about ingoing and outgoing segments of the route. bool KeepTurnByAlignedAlternatives(TurnCandidates const & possibleTurns, TurnInfo const & turnInfo, NumMwmIds const & numMwmIds) { // Note. The bigger road the less HighwayClass value. ftypes::HighwayClass outgoingRouteRoadClass = turnInfo.m_outgoing.m_highwayClass; // The turn should be kept if there's no any information about feature id of outgoing segment // just to be on the safe side. It may happen in case of outgoing segment is a finish segment. Segment firstOutgoingSegment; if (!turnInfo.m_outgoing.m_segmentRange.GetFirstSegment(numMwmIds, firstOutgoingSegment)) return true; Segment inversedLastIngoingSegment; if (!turnInfo.m_ingoing.m_segmentRange.GetLastSegment(numMwmIds, inversedLastIngoingSegment)) return true; inversedLastIngoingSegment.Inverse(); for (auto const & t : possibleTurns.candidates) { // Let's consider all outgoing segments except for // (1) route outgoing segment // (2) a U-turn segment (inversedLastIngoingSegment) if (t.m_segment == firstOutgoingSegment || t.m_segment == inversedLastIngoingSegment) continue; ftypes::HighwayClass const highwayClass = t.m_highwayClass; // Note. The bigger road the less HighwayClass value. if (static_cast<int>(highwayClass) < static_cast<int>(outgoingRouteRoadClass)) { // any alternative turn to bigger road causes keep turn return true; } else if (static_cast<int>(highwayClass) == static_cast<int>(outgoingRouteRoadClass)) { // any alternative turn to similar road causes keep turn if turns less then 70 degress (wider than SlightTurn) if (fabs(t.m_angle) < 70) return true; } else { // any alternative turn to smaller road causes keep turn if turns less than SlightTurn if (IsGoStraightOrSlightTurn(IntermediateDirection(t.m_angle))) return true; } } return false; } ```

biodranik commented

2022-04-14 00:08:23 +00:00

(Migrated from github.com)

Awesome! What cases are still not detected properly?

CC @vng

Awesome! What cases are still not detected properly? CC @vng

vng commented

2022-04-14 06:54:35 +00:00

(Migrated from github.com)

@AntonM030481 Please, make a PR with your changes.

AntonM030481 commented

2022-04-14 07:02:26 +00:00

(Migrated from github.com)

In fact it solved all my simple cases with unnecessary SlightTurns. Compare:

In fact it solved all my simple cases with unnecessary SlightTurns. Compare: <img width="455" alt="image" src="https://user-images.githubusercontent.com/85622715/163331347-6856830b-ad64-4802-b23b-2a48a90e4ad1.png"> <img width="408" alt="image" src="https://user-images.githubusercontent.com/85622715/163330863-3664149e-ca22-4a5d-b8be-cec40f0aa4fb.png">

AntonM030481 commented

2022-04-14 07:34:20 +00:00

(Migrated from github.com)

BTW this helped me to identify road mapping issues.
E.g. here turn is kept, because of allowance of going back using the primary road link.
The question is only about TurnSlightLeft direction.
Maybe we need to convert it to GoStraight if all alternatives turn more then 90 degress:

This is more tricky one. Let's agree that direction is still needed here.
But TurnSlightLeft is questionable again.
Maybe we need to convert it to GoStraight if all alternatives turn more then current turn in the same direction:

BTW this helped me to identify road mapping issues. E.g. here turn is kept, because of allowance of going back using the primary road link. The question is only about TurnSlightLeft direction. Maybe we need to convert it to GoStraight if all alternatives turn more then 90 degress: <img width="808" alt="image" src="https://user-images.githubusercontent.com/85622715/163334447-5c0a6b80-b927-439a-9980-2a12bb83d61d.png"> This is more tricky one. Let's agree that direction is still needed here. But TurnSlightLeft is questionable again. Maybe we need to convert it to GoStraight if all alternatives turn more then current turn in the same direction: <img width="811" alt="image" src="https://user-images.githubusercontent.com/85622715/163335771-b92607f3-a81f-48fb-bdde-1c53fcb1aa93.png">

biodranik commented

2022-04-14 11:54:41 +00:00

(Migrated from github.com)

Probably "go straight" is a good option.
Alternatively, using Keep Left in the first one would be safer for drivers if there is an alternative right turn/U-turn (the idea is to avoid a wrong right turn). In the second example, the current instruction is obviously a bug, the proper instruction should be Keep Right, not Left, to avoid the obviously incorrect left turn/link. Keep Straight would also be ok.

Probably "go straight" is a good option. Alternatively, using Keep Left in the first one would be safer for drivers if there is an alternative right turn/U-turn (the idea is to avoid a wrong right turn). In the second example, the current instruction is obviously a bug, the proper instruction should be Keep **Right**, not Left, to avoid the obviously incorrect left turn/link. *Keep Straight* would also be ok.

biodranik commented

2022-04-14 11:55:23 +00:00

(Migrated from github.com)

In any case, your current implementation is better than the existing one. Let's check it in reality. Can you please create a PR?

AntonM030481 commented

2022-04-14 15:11:30 +00:00

(Migrated from github.com)

In any case, your current implementation is better than the existing one. Let's check it in reality. Can you please create a PR?

Sure. This is my 1st pull request to GitHub, so it's a bit challenging :)
#2397

> In any case, your current implementation is better than the existing one. Let's check it in reality. Can you please create a PR? Sure. This is my 1st pull request to GitHub, so it's a bit challenging :) #2397

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[Navigation] Unnecessary SlightTurn directions in some situations #2262