Matching plugin: add a no u-turn properties

[kaligrafy]

Would it be possible to add a no_uturn_in_matching flag properties in the lua profile so matching algorithm doesn't create uturns even when angle is large?

For now, I just commented lines 37 to 49 in /src/engine/plugins/match.cpp and it works well, but a parameter would be awesome.

Thanks!

[daniel-j-h]

Not sure what the general idea behind this was cc @TheMarex - but it is possible to add such a parameter for sure. Here's how you can do it:

• adapt filterCandidates to take a boolean
• on the callsite pass a boolean based on the MatchParameters which HandleRequests gets
• add a parameter to MatchParameters (in a backwards compatible way)
• add a parameter to the query parser: MatchParametersGrammer
• add tests to the match grammar unit tests

Feel free to start this and open a PR early on where we can help you in case you're stuck :)

[kaligrafy]

Thanks a lot!

In fact, the matching algorithm is quite useful to calculate shortest path when waypoints are approximate such as bus stops we need to serve in a 50m radius around a station location (this helps us determine the best precise location for each stop in a route during design phase). But as you know, allowing u-turns for buses is completely unrealistic. I'll prepare the PR. Thanks!

[daniel-j-h]

Wow that's a cool use-case! Thanks for doing a PR!

[kaligrafy]

Can somebody check the changes in my fork before I post a PR? Thanks!

[daniel-j-h]

Just do a pull request 👍 this way we can leave comments directly on the code.