3

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?

Improve this question

1 Answer 1

Reset to default
6

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.

Improve this answer
2
  • 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

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.