I am working in QGIS and I have this road shapefile (singlepart polygon). How to split this polygon into a multipart polygon by splitting geometry at that point when the orientation changes? In order to have several street geometries. enter image description here

  • Have you tried the advanced digitizing toolbar?
    – Erik
    Apr 19, 2023 at 8:48
  • Thanks for the reply. I can't do this manually by using the advanced digitizing toolbar because the study area has a very big extension. My goal is to follow a procedure by using some gis tools.
    – GiuliaG
    Apr 19, 2023 at 9:03
  • What have you tried then?
    – Erik
    Apr 19, 2023 at 9:59
  • I've tried to divide the vector geometry by using the "subdivide" option, but It doesn't work well. Do you have any suggestions?
    – GiuliaG
    Apr 19, 2023 at 10:15

2 Answers 2


If you're willing to use GRASS GIS, then the v.clean module splits all linestrings at all intersections. You would call the command with the option:

v.clean input=<your road vector> output=roads_clean tool=break,rmdupl thresh=0,0 

You will, of course, have to import the roads layer into GRASS first.


Ah wait, these are polygons?? Then my suggestion won't work. :-( I think you'll have to shrink the polygons down to centerlines, then split the centerlines layer. (BTW: "single part" refers to a layer that's split up. "Multipart" indicates a layer with a single polygon made up of many individual segments)

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