[Qgis-user] Area calculation tools

[Stephane Goldstein]

Hello.
I've noticed that there are in the feature area calculated by Vector >
Geometry Tools > Export/Add Geometry Columns" vs. using $area in the field
calculator.

For the same polygon I got
151 482 883.964722 m2 for the first one and
152 548 334.467394 m2 for the second.
This is a 106ha difference for a 15k ha area.
Does someone know which one of the tools is more precise, and why ?

Thanks

Stephane
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