I have a polygon on my map and I want to resize it in that way I add X km to all of the vertexes. Any idea?

  • Resize relative to what? Adding N kilometers to the y dimension and the x dimension of every vertex will simply move the polygon farther away from the zeropoints of the x and y axes of the projection (for latitude, the equator, for example). Jan 30, 2013 at 21:50
  • You do realise that for most polygons this will result in a modified shape? Jan 30, 2013 at 21:52
  • I want to do the same like this: obj.geometry.resize(2, obj.geometry.getCentroid() ); instead of 2 there will be x-km. I'm sorry for the misunderstanding...
    – user14734
    Jan 30, 2013 at 22:17
  • Closely related: gis.stackexchange.com/a/29893.
    – whuber
    Jan 30, 2013 at 22:31

2 Answers 2


The spatial operation you need is called BUFFER and is implemented in most geographical database managers

  • +1 for this answer... although a general question is, why don't you just redraw the polygon to the specifications that you want?
    – Andy TIce
    Jan 31, 2013 at 5:03

if you use geodjango on server side, you can use buffer method in Topological Methods.

polygon.buffer(1000) # 1 km buffer for your polygon

i hope it helps you...

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