I have a map scan (scale 1:500, CRS probably: ETRS89 / UTM Zone 33N) and want to georeference it. Therefore, I set a ground map (Google Satellite, CRS: WGS 84/ Pseudo Mercator). After georeferencing, the scaling of my map is incorrect. My area has grown from 1250 m² to 3000 m². On the fly projecting is enabled and I also set the project CRS manually to Pseudo Mercator.

Does anyone have any idea of where I'm going wrong?

1 Answer 1


Because of Pseudo Mercator? Pseudo Mercator is not a proper Coordinate System to measure areas. Depending where you are on Planet Earth, there can be huge differences in area-size compared to other coordinate systems that try to reduce distortion.

  • Maybe it is my fault, but I cannot change the CRS of my basemap (Pseudo Mercator). I'm loading the basemap by using the Openlayer plugin.
    – Kay Rail
    Oct 17, 2017 at 13:49
  • My advice, use the Quickmapservices Plugin (to get Google Satellite: Settings --> More Services). Set your project CRS to ETRS89 / UTM Zone 33N (you do not have to change the CRS of your background map) and do also the georeferencing with UTM.
    – AndreasK
    Oct 17, 2017 at 13:57

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