I have two shapefiles, a polygon shapefile (lake) and a line shapefile (boudary) I want to create a new shapefile "polygon to the north of the boundary"

I want to create a new polygon "area north of the border line"

What tool can I use in QGIS or other free GIS for this task?

2 Answers 2


There is a QGIS plugin called Digitizing Tools:

The documentation says:

Split selected features with selected line(s) from another layer

applies to: line and polygon layer (multi or single part)

Splits all selected features of the active layer with the selected line features of another layer. The splitting creates new features (not multi features). Each new feature resulting from being split retains its original attributes.

  • 1
    it worked perfectly! Jul 8, 2014 at 20:53
  • @jirikadlec2 fantastic! Jul 8, 2014 at 22:48
  • In my experience, it can only split with one selected line at a time (not selected lines). I get the following error message if I try more than one: "Please select only one feature to split with." Nov 29, 2017 at 21:46
  • It split my polygon but only kept one half. The other half is gone.
    – Liz
    Oct 12, 2018 at 0:35
  • You may have used 'cut' instead of 'split' Oct 12, 2018 at 0:48

The answer provided year before seems to be outdated. An option working with newer versions of QGIS (I'm currently using 3.26):

Menu processing > Toolbox > Split with lines

Set the polygon as Input layer and the line as Split layer - and you're done.

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