[Navigation] TurnSlightLeft or TurnLeft directions for rightmost turn #2417

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opened 2022-04-18 08:04:04 +00:00 by AntonM030481 · 6 comments

AntonM030481 commented

2022-04-18 08:04:04 +00:00

(Migrated from github.com)

It was mentioned in #2262
Here we have TurnSlightLeft direction.
Why? Because way is 10.2 degrees left from current direction vector.
Current angle limit for GoStraight is standard 10 degrees from left side in this situation.
Such situation (way goes though rightmost turn) is handled specifically now, so angle limit can be easily customised.
We can extend this limit to e.g. 20 degrees for such situation, so we will have GoStraight in pictured case.

The question is what to do in rare cases when both possible turns go significantly left from current direction vector.
E.g. selected (rightmost) turn is 30 degrees left and another turn is 40 degrees left.
For sure it's incorrect to give directions TurnLeft or TurnSlighLeft if we need rightmost turn.
Should we continue give GoStraight direction after proposed 20 degrees limit? The reason is that our selected rightmost turn is the most straight turn in such situation.

It was mentioned in #2262 Here we have TurnSlightLeft direction. Why? Because way is 10.2 degrees left from current direction vector. Current angle limit for GoStraight is standard 10 degrees from left side in this situation. Such situation (way goes though rightmost turn) is handled specifically now, so angle limit can be easily customised. We can extend this limit to e.g. 20 degrees for such situation, so we will have GoStraight in pictured case. <img width="811" alt="image" src="https://user-images.githubusercontent.com/85622715/163335771-b92607f3-a81f-48fb-bdde-1c53fcb1aa93.png"> The question is what to do in rare cases when both possible turns go significantly left from current direction vector. E.g. selected (rightmost) turn is 30 degrees left and another turn is 40 degrees left. For sure it's incorrect to give directions TurnLeft or TurnSlighLeft if we need rightmost turn. Should we continue give GoStraight direction after proposed 20 degrees limit? The reason is that our selected rightmost turn is the most straight turn in such situation.

AntonM030481 commented

2022-04-18 08:39:54 +00:00

(Migrated from github.com)

@vng @biodranik
I can easily fix it in proposed way (anyway it will be better then current behaviour).

@vng @biodranik I can easily fix it in proposed way (anyway it will be better then current behaviour).

biodranik commented

2022-04-18 08:49:27 +00:00

(Migrated from github.com)

Let's do it go straight. It would be better than now. And then we'll debug and find some rare cases and think about a better solution.

AntonM030481 commented

2022-04-19 18:27:03 +00:00

(Migrated from github.com)

During modification some bugs were found.
Currently in the process of fixing and refactoring.

During modification some bugs were found. Currently in the process of fixing and refactoring.

biodranik commented

2022-05-05 21:19:10 +00:00

(Migrated from github.com)

For a proper UX, we need to distinguish between displayed arrows and announced directions. So visually it should be left + slight left, but the announcement should say "keep right". What do you think?

AntonM030481 commented

2022-05-06 06:43:41 +00:00

(Migrated from github.com)

If route direction is rightmost and visually goes (slight) left, it will be converted to SoStraight.
Next it will be converted to SlightRight if another possible turn is slight left too.

So, for rightmost route:

left+left will be announced as go_straight (Note1).
left+slight_left will be announced as go_straight (Note 1 and 2).
slight_left+slight_left will be announced as slight_right (Note 1).

Note 1. This is simplified logic. Directions are compared by angle to be differs enough, not by categories (straight vs slight), to correctly handle border cases.
Note 2. This turn can be discarded if route road is bigger depending on priorities and angles.

It should be considered also, that when the roads are curved, it's very arguable if it is visually left or slight_left, slight_left or go_straight, go_straight or slight_right.
In many cases to play safe it's better to apply similar logic for arrows as for announces.

E.g. it is not easy to say what arrows should be here for red car
(announce will be go_straight or discarded):

Should we draw something like this?

- If route direction is rightmost and visually goes (slight) left, it will be converted to SoStraight. - Next it will be converted to SlightRight if another possible turn is slight left too. So, for rightmost route: 1. left+left will be announced as go_straight (Note1). 2. left+slight_left will be announced as go_straight (Note 1 and 2). 3. slight_left+slight_left will be announced as slight_right (Note 1). Note 1. This is simplified logic. Directions are compared by angle to be differs enough, not by categories (straight vs slight), to correctly handle border cases. Note 2. This turn can be discarded if route road is bigger depending on priorities and angles. It should be considered also, that when the roads are curved, it's very arguable if it is visually left or slight_left, slight_left or go_straight, go_straight or slight_right. In many cases to play safe it's better to apply similar logic for arrows as for announces. E.g. it is not easy to say what arrows should be here for red car (announce will be go_straight or discarded): <img src = "https://user-images.githubusercontent.com/85622715/167090137-fac1c0a8-15bc-4df8-8607-0e1007485d34.png" width="300" height="auto"> Should we draw something like this? <img src = "https://user-images.githubusercontent.com/85622715/167102371-3f63dd56-4cf0-498a-85a5-4207db88d2f9.png" width="200" height="auto">

AntonM030481 commented

2022-05-06 13:49:11 +00:00

(Migrated from github.com)

Currently rule for correction of go_straight to slight_turns is applied rather often.
But the rule of Leftmost/Rightmost angle when direction is changed to opposite is applied 2 times in our tests.

Germany_ShuttleTrain_TurnTest
Russia_Moscow_LeningradskiyPrptToTTK_TurnTest:

In the test from the top organicmaps/organicmaps#2417 (comment) such turn is discarded.

Currently rule for correction of go_straight to slight_turns is applied rather often. But the rule of Leftmost/Rightmost angle when direction is changed to opposite is applied 2 times in our tests. 1. Germany_ShuttleTrain_TurnTest <img width="741" alt="Germany_ShuttleTrain_TurnTest" src="https://user-images.githubusercontent.com/85622715/167144513-154d9959-8dcc-47b5-a4b1-24d01a8fbd80.png"> 2. Russia_Moscow_LeningradskiyPrptToTTK_TurnTest: <img width="1131" alt="Russia_Moscow_LeningradskiyPrptToTTK_TurnTest" src="https://user-images.githubusercontent.com/85622715/167144546-45707852-b2ec-44a3-8a7a-c85fb3eec19f.png" width='300' height = 'auto'> In the test from the top https://git.omaps.dev/organicmaps/organicmaps/issues/2417#issue-1206792896 such turn is discarded.

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