I'm looking to route a road network using the LRS plugin and it fails to work on items with the same start/end points.

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Is there a way around this or is there a tool I can use to simply trim a meter off the roundabouts to then use that as an input layer?

1 Answer 1


Even if your polyline is a closed loop it still have a first and last vertices so if you locate a linear event from the m value of the first vertices to the m value of the last vertices it should cover the whole loop.

The complication is when you want to locate events only for part of the loop and you cross the start/end point. In this case my solution is to create two separate event on each side (so a 20 unit event on a 180 unit loop would be cut like one event from 0 to 10 and a second one from 170 to 180)

  • I can't even get to the locating features part of the process. It won't even route/calibrate the roundabouts
    – Alan Carr
    Mar 29, 2022 at 15:19
  • If tou don't have to many roundabout you may try to manualy calibrate by editing the m value of each vertex, another way would be to slightly open the roundabouts before calibrating then closing it (your calibration will be of by a few cm) again feasible only for a limited number of features
    – J.R
    Mar 29, 2022 at 18:05

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