Your network contains self-intersecting polylines
- Self intersection is usually a result of poor digitising. They can be hard to spot if the intersection is very small. Experience has shown that it is typically the misplacement of a single vertex.
- A self-intersecting polyline can be corrected by entering edit mode, setting the task to "modify feature", enabling the Edit Tool button (
), right click on the incorrect vertex and delete or move it.
- In the example image below a single vertex is misplaced (red circle). Delete vertex has been selected from the context menu.

