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<p>Hi,<br>
</p>
<p>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</p>
<p>$area : (Ellipsoidal area)<br>
</p>
<p>area($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.)<br>
</p>
<p>I would use $area</p>
<p>Nicolas<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 2021-01-25 1:01 p.m., Azzurra
Lentini wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAJ3ZhxqGSYKit92RfGvFJcZ473nBxyEDbsQY2eamc7WnSDrHpg@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">
<div class="gmail_default" style="font-family:tahoma,sans-serif">Hi
to all,</div>
<div class="gmail_default" style="font-family:tahoma,sans-serif">I
calculated the area of a shape file polygon with 2 different
tools:</div>
<div class="gmail_default" style="font-family:tahoma,sans-serif">the
standard one from field calculator and the other method using
a plugin "geometry calculator".</div>
<div class="gmail_default" style="font-family:tahoma,sans-serif"> Do
you know why I obtained 2 different results?<br>
</div>
<div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">10144312,54 square
meter</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">10148071,71
square meter
<br>
</div>
<br>
</div>
<div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">I am using Qgis 3.10
with grass and in the plugin I set up to use CRS of the
project. </div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">Thanks, Azzurra</div>
<br>
</div>
-- <br>
<div dir="ltr" class="gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">Lecturer GIS University "Roma Tre"<br>
</div>
<div dir="ltr">Consultant Environmental Risk
Prevention and Hydrogeology<br>
AZZURRA LENTINI </div>
<div dir="ltr">++++++++++++++++++++++++++<br>
Italy Mobile Tel.: **(39) 338 24 40 676<br>
++++++++++++++++++++++++++<br>
SKYPE azzurrahydro<br>
++++++++++++++++++++++++++</div>
<div>
<p class="MsoNormal"
style="margin-bottom:0.0001pt;background-image:initial;background-position:initial;background-repeat:initial;line-height:normal"><b><u><span
style="font-size:12pt;font-family:Arial,sans-serif;color:blue"><a
href="mailto:azzurralentini@gmail.com"
style="color:rgb(17,85,204)"
target="_blank" moz-do-not-send="true">azzurralentini@gmail.com</a></span></u></b></p>
<p class="MsoNormal"
style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-repeat:initial"><b><u><span
style="font-size:12pt;font-family:Arial,sans-serif;color:blue"><a
href="mailto:azzurra.lentini@uniroma3.it"
style="color:rgb(17,85,204)"
target="_blank" moz-do-not-send="true">azzurra.lentini@uniroma3.it</a> </span></u></b><b><u><span
style="font-size:12pt;font-family:Arial,sans-serif;color:blue"> </span></u></b><br>
</p>
</div>
<div dir="ltr">++++++++++++++++++++++++++<br>
*Par respect pour l'environnement,*<br>
<br>
*n'imprimez ce mail qu'en cas d'absolue
nécessité*</div>
</div>
<div dir="ltr"> <br>
<br>
<br>
<br>
<br>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
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</blockquote>
<pre class="moz-signature" cols="72">--
Nicolas Cadieux
<a class="moz-txt-link-freetext" href="https://gitlab.com/njacadieux">https://gitlab.com/njacadieux</a></pre>
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