Roundabout instruction improvement

[jansoe]

As a follow up to the implementation of roundabout instructions (#316) some improvements are yet to be implemented:

• [x] #424
• [x] improved detection of direction of rotation by not relying on turn geometry, but purely on the edges' order. For a clean implementation there should be no CH shortcuts in the graph (#116)
• [ ] a more accurate assesment of the transit angle through the roundabout in case of drive-up ways. To this end either one calculates entrance/exit direction not only from the last two waypoints but interpolates across the last X meters, or one avarages waypoints of both the incoming and outgoing direction of the edge.
• [x] more fine grained text instructions and rephrase "take exit X in direction dummy street" to "take exit X onto dummy street"
• [ ] exit numbers are counted as exits the vehicle (i.e. encoder) could take. This might lead to confusion as e.g for bikes this could increase the exit number (https://graphhopper.com/maps/?point=52.513955%2C13.344462&point=52.511598%2C13.357036&vehicle=bike&elevation=true&layer=TF%20Cycle) but a user might assume that only paved streets are counted. Vice versa this could reduce the number of counted exits for trucks as some exits might be prohibited for them.
• [x] There is a counting problem if the incoming edge its last node is identical to the first node of the next outgoing edge. See the screenshot of miniui (right side), which is taken from old data in the file core/files/monaco.osm.gz here will be fixed with #354
  • [x] A roundabout instruction bug. See this route. It say: at roundabout take exit 2, but it should be exit 1. This is probably created by this track, that is probably seen as the 1st exit.
  • [ ] Another bug is here where all leaving roads are handled as first exist. Caused potentially from strange tagging.

[devemux86]

I propose to make public the RoundaboutInstruction.getExitNr to be able to handle more flexible the RoundaboutInstruction (like the others) by getting its elements.

[karussell]

(If so, please rename to getExitNumber :))

[devemux86]

It would be also helpful if the RoundaboutInstruction's finished and continuedStreet variables get public get methods, since they participate in instruction building.

[jansoe]

please note that isContinuedStreet is already public. I will make getExitNr public and rename it to getExitNumber.

I hesitate to make finished public as it's main purpose is internal consitency control, but you are right it takes part in the instruction building if the goal is within a roundabout. With the upcoming improved roundabout instruction in mind I would introduce an indicator variable that indicates if a roundabout either has to be entered and left | only entered | only left.

[devemux86]

I know you have mentioned that the roundabout instructions are to be improved. Because right now do we really need the instruction with 0 exit? Isn't confusing for the user?

[jansoe]

Yes I think it might be confusing. But I also think it is a very unusal case that a route is to end within a roundabout and therefore this instruction is temporarly acceptable. I totally agree that the refined instructions should be available as soon as possible, but I also wanted to give the community a chance for feedback.

[karussell]

In general we should probably use "car_access" as reference so that if a bike cannot use the motorway the road is still counted.

On the other hand insignificant roads for car should be somehow ignored: https://graphhopper.com/maps/?point=51.49277%2C-0.28221&point=51.49095%2C-0.283563&profile=car