[Qgis-user] Area calculation tools

[ralfwessels]

Hi Stephane,
if you calculate areas (or length) with the "Add geometry Columns"-Tool, the
results depend on the settings you can make under "Calculate using". Here
you have the options Layer CRS, Project CRS or Ellipsoid.
Ellipsoid is calculating with the curvature of the earth (so far I know) and
the others depending on the CRS' of the layer or the project (when 'on the
fly' CRS transformation is enabled).
If you are using $area in the field calculator it depends if 'on the fly'
CRS transformation is enabled or not.
If it is not enabled it calculates with the layer CRS, if it is enabled it
should calculate with the project CRS.

These are my testing experiences so I'm not 100% sure, but maybe there is
someone who has more informations about this topic.
ralf





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