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I have the following problem in QGIS:

I try to create voronoi polygons based on a shapefile (points; standard WGS84). The newly created voronoi polygons layer seems to be ok for the WGS84 CRS. But when I swith into Pseudo Mercator CRS (3857) then the voronoi polygons are (of course) not representing the correct voronoi polygon layer and the polygons are not representing areas according to the neares points of the souce layer for that CRS.

Is there a way, how to create new voronoi polygons layer based on the same source shapefile (standard WGS84), but so that the final voronoi layer would work correctly in the Pseudo Mercator projection?

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    What do you mean polygons are not correct? If you have points and polygons(voronoi) and change the CRS of polygons only, then polygons and points won't fit. I am not sure what do you really mean, could you provide picture example? – geo_dd Sep 17 '15 at 15:33
  • Try Vector -> Geometry Tools -> Densify Geometries on the polygon layer before changing the CRS. – AndreJ Sep 18 '15 at 3:49
  • Voronoi polygons created in spherical coordinates (such as WGS84) will be wrong because of the severe distance distortions. The same goes for Pseudo-Mercator, although to a lesser degree within small areas (because it is conformal). – whuber Feb 13 '16 at 13:42
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You could maybe simply reproject the source point to whatever projection you are working in. Then create Voronoi polygons from those points.

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