I'm working with some shapefiles I didn't create and very frequently, when I try to split some of the polylines using the Split Features function, I am left with disjoint parts and more than two segments.

I believe this is related to the vertices being "out of order," but how do I clean up the ordering?

Step 1

Step 2

Step 3

  • 1
    perhaps v.clean.break combined with something like dissolve or merge to re-combine the line segments – csk Feb 13 '18 at 20:22
  • Did you try running the "Vector -> Geometry Tools -> Check geometry Validity"? – NettaB Feb 14 '18 at 13:23
  • I did try this, but it didn't yield too much fruit. What seems to work best is to first (before cutting one of these vexing lines), to try to "split selected multi-part feature into single part." Then, I proceed with the "split feature" function. I just wish there were a way to know that the feature was multi-part before trying to split it. – jeffme Feb 15 '18 at 16:30
  • Following up here, what I think usually ends up happening is that the parts aren't able to truly be merged b/c of small errors in the topologies of the geometry - e.g. segments that aren't able to be merged at common vertices, etc. So, the sequence is this: 1. Recognize the dynamic highlighted above 2. Split selected multi-part_feature into single part 3. Go back to see why there wasn't a clean merge in the past 4. Fix the problems (e.g. use snap to align vertices at ends of segments) 5. Re-merge the parts 6. Inspect to confirm that the re-merge worked – jeffme Feb 25 '18 at 20:19

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