[Qgis-user] differences measuring area with field calculator and plugin geometry calculator

[Nicolas Cadieux]

Hi,

One uses the ellipsoidal area based on the CRS and one does not (or uses 
a different formulas for the ellipsoidal area).  Go to the field 
calculator and generate temporary fields.   In the field calculator use 
the following formulat

$area  : (Ellipsoidal area)

area($geometry) : (non ellipsoidal area based on the geometry. Results 
may be weird if your file is in Long-Lat but they should correspond to 
your numbers.)

I would use  $area

Nicolas


On 2021-01-25 1:01 p.m., Azzurra Lentini wrote:
> Hi to all,
> I calculated the area of a shape file polygon with 2 different tools:
> the standard one from field calculator and the other method using a 
> plugin "geometry calculator".
>  Do you know why I obtained 2 different results?
> 10144312,54 square meter
> 10148071,71 square meter
>
> I am using Qgis 3.10 with grass and in the plugin I set up to use CRS 
> of the project.
>
> Thanks, Azzurra
>
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-- 
Nicolas Cadieux
https://gitlab.com/njacadieux

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