reflect driving side in U-turn symbol

[MoKob]

For the query, http://map.project-osrm.org/?z=18&center=51.046407%2C13.741493&loc=51.046628%2C13.741708&loc=51.046274%2C13.741273&hl=en&alt=0

the frontend shows a straight arrow:

The response for the same query (https://router.project-osrm.org/route/v1/driving/13.741708,51.046628;13.741273,51.046274?steps=true) shows the indications:

{"intersections":[{"lanes":[{"valid":false,"indications":["uturn"]},{"valid":false,"indications":["left"]},{"valid":true,"indications":["straight"]},{"valid":false,"indications":["straight"]}

The shown arrow should indicate a reverse, which is not the case right now.

/cc @freenerd

[daniel-j-h]

Possibly related: multiple indications per lane are broken #192

[daniel-j-h]

Missing uturn case here:

osrm-frontend/src/itinerary_builder.js

Lines 26 to 45 in a486a1e

	case 'right':
	case 'sharp right':
	icon = 'turn-right';
	break;
	case 'slight right':
	icon = 'bear-right';
	break;
	case 'left':
	case 'slight-left':
	icon = 'turn-left';
	break
	case 'sharp-left':
	icon = 'bear-left';
	break;
	case 'straight':
	case 'none':
	default:
	icon = 'continue';
	break;
	}

[daniel-j-h]

Fixed http://map.project-osrm.org/?z=18&center=51.046407%2C13.741493&loc=51.046628%2C13.741708&loc=51.046274%2C13.741273&hl=en&alt=0

[emiltin]

It would be nice if u-turn icons would indicate a counter clockwise turn (in locations with right-side driving).

[daniel-j-h]

@emiltin the frontend does not know about left- / right side driving. It's not even in the osrm response.

We could add country polygons and do a point in polygon check for the maneuver's location in the frontend. But then again, looking at the currently 40 open issues, I think there are other things to prioritize :)

(Btw if you want to lend a hand feel free to grab some issues, our frontend-fu is somewhat weak :/)

[freenerd]

I did not implement u-turn symbols because of the directions mismatch.

Doing the left/right-hand driving approach is big to do.

One easy thing we could add on the frontend side are u-turns on the left lane have a left-u-turn symbol, u-turns on the right a right-u-turn symbol. This would at least fix the obvious mismatch we have in the screenshot above.

[daniel-j-h]

Related: uturn left vs uturn right in response Project-OSRM/osrm-backend#3077 (v6)

[DennisOSRM]

We now have a classifier to detect which area of driving side a road segment is in: https://github.com/Project-OSRM/gauche-rs

Once this is wired into the extractor, it's simple and easy derive driving side per segment, to analyze turn with or against traffic, and then to expose this in the UI. That being said it's mostly a backend issue, and not necessarily a frontend task.