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Inverse route does not necessarily use inverse instructions


#1

First of I want to start thanking the community and especially the core team of GH for the great work they’ve done and the great deal of improvements they’ve made on it in the past few years.
GH is trying to not give to many instructions to a user for good reason. So it is giving a “continue on street” if the road you’re “turning onto” has the same name. However this happens to be confusing to some users.

For example consider this route

The user will get a route with instructions indicating to continue on B2. However users and street signs indicate that normal human beings see this as turning left. The reverse route

even tells the user to slightly turn right. The question here is if anyone else is having this issue and if plans to change this exist.

Best,

wuenschelroot


#2

Hi wuenschelroot,

thanks for the request.

In general this is really hard to solve. GraphHopper currently does not support turn lanes. There is a PR for this. Which could in the future help with generating turn instructions.

Currently, GraphHopper calculates turn instructions mostly by looking at the geometries of the route and a small set of tags.

BTW here are both situations in Mapilary, 1 and 2.

I think navigation should be still possible, since the left turn, could be still considered as a continue without the signs and arrows on the pavement. However, a left-turn would be better suited.

Cheers,
Robin