I am working on a publication and would like to make my schematic visually pleasing. The amount of detail is too high and the image would be better If I could simplify and smooth my line and polygon vectors. Ideally it would minic smooth Bezier like curves. (Curves are not yet supported in QGIS so searching an alternative)

I've tried many many settings in QGIS, primarily the v.generalize tool but I either get errors or the results still has sharp corners.

enter image description here

A close up reveals the ugly sharp corners of the vectors. enter image description here

And I would like to get something like this: enter image description here

Is there a simple way to simplify the vectors into smooth lines? Alternativily, which settings in GRASS v.generalize should I use?

Related question: Is there a way to render lines with a smooth (bezier) curves in QGIS?

It seems like v.generalize with Chaiken algorithm could do the trick. Searching for the correct settings. (Trial and error)

Shapefiles can be found here

  • 1
    Have you checked several plugins, namely SmoothLine and Cartographic Line Generalization?
    – Taras
    Feb 4, 2019 at 13:54
  • QGis 3.4 has the tool "smoothgeometry" in the toolbox. This might be what you're looking for.
    – Erik
    Feb 4, 2019 at 13:55
  • the build-in smooth function doesn't result in the desired output. I've tried multiple offset and angle settings.
    – RutgerH
    Feb 4, 2019 at 13:59
  • 1
    look at 2 options of hydrography of soft and rough force, maybe they will suit you...drive.google.com/file/d/1o5Hz_toFHBCFMoZiD2Wt6QfUuNizu7_c/… Feb 4, 2019 at 19:31
  • 1
    This is usually a two step process: simplify the lines first to remove the unwanted detail, and then smooth the result
    – ndawson
    Feb 4, 2019 at 19:46

1 Answer 1


You can use a geometry generator in styling as symbol layer style and smooth function. The advantage of this solution is that the geometry is intact.

Smooth 0: Geomoetry Generator - Smooth 0

Smooth 5: Geomoetry Generator - Smooth 5

  • this looks promising. The only issue is that my shapefile consists of multilines (I've added a download link). At each end of a single line, the corner remains sharp. I will probably have to merge/dissolve to get the result I want.
    – RutgerH
    Feb 5, 2019 at 10:29
  • Is there a way to save/export the smooth(ed?) geometry as a new vector file?
    – BERA
    Mar 6, 2020 at 14:29
  • 1
    @BERA in processing you will find generate geometry algorytm.
    – GSienko
    Mar 6, 2020 at 14:42
  • It doesn't give very nice results for closed loops at the vertex where the loop closes. Is there anyway to improve this? Mar 5, 2023 at 19:12

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