Is it possible with QGIS to increase or reduce features (polygons or lines already drawn) proportionally? Preventing me to redraw several times new polygons :)

enter image description here

See picture above: Making it possible to resize for example the green polygon to the size of the red polygon (the polygons are build by the plugin "Rectangles ovals digitizing").

In ArcGIS, this can be accomplished by using the Scale tool to resize an individual feature. I haven't found a solution in the QGIS-Guide.

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    QGIS is a Geographic Information System not a Drawing Program like InkScape, Adobe Illustrator or what ever. Polygons, lines are defined by points, which correspont to coordinates on the ground. Do you mean drawing (= output on paper) to a different scale??
    – Kurt
    Commented Oct 2, 2012 at 18:28
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    @Kurt thank's for the answer; if I remember rightly ArcGIS can increase or reduce the size of features with the new drawing tools. No not the output on paper, I was thinking about editing the features in polygons.shp or lines.shp; so that I can increase or reduce the features size manually but proportional. best regards, phil
    – philmyer
    Commented Oct 2, 2012 at 18:50
  • @underdark Thank's for having edited. I will try to do it right next times.
    – philmyer
    Commented Oct 3, 2012 at 9:54
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    Probably need more detail on the purpose, do you want to have one point fixed and the other 3 sides change, or the centroid fixed, the operation occurs with the mouse and some eyeball extent or by a ratio input to a dialog?
    – Willy
    Commented Oct 3, 2012 at 10:53
  • @Willy I added a picture on the initially question. Most of the time I would say the centroid may stay fixed and the size can be changed by hand (eyeball extend). I can still move it to the right position after having changed the size. I hope it's clearer now. Do you have any idea? Thank's in advance for any tip.
    – philmyer
    Commented Oct 4, 2012 at 9:55

1 Answer 1


Looking at the picture, you could do something like this with buffers. The QGIS buffering tool (from under the Vector menu) will accept negative buffer values. Tick 'Dissolve buffer results'.


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