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<p>Hi Herbert,</p>
<p><br>
</p>
<p>You are using a Mercator based projection to calculate distances
[1]. It was not designed for distance calculations.</p>
<p><br>
</p>
<p>Can you reproject to your own national/local projected coordinate
system? Compute the buffers using it and compare the results.<br>
</p>
<p><br>
</p>
<p>Regards,</p>
<p><br>
</p>
<p>Jorge<br>
</p>
<p><br>
</p>
<p>[1] <a class="moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/Mercator_projection">https://en.wikipedia.org/wiki/Mercator_projection</a></p>
<p><br>
</p>
<div class="moz-cite-prefix">Às 14:21 de 14/01/19, Herbert Faber
escreveu:<br>
</div>
<blockquote type="cite"
cite="mid:AM0PR06MB563551035B2FB0B36D05F0C9FE800@AM0PR06MB5635.eurprd06.prod.outlook.com">
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<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri">Dear all,</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri">When I put ring buffers arond dot objects, the
diameter doesn't come out as I would expect.</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri"><br>
</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri">For instance, when I try to make ring buffer
with a distance of 100 meter and 25 segments around a dot
object. The diameter of the buffer turns out to be approx 126
m when I measure it with the ruler tool.</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri"><br>
</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri">What am I doing wrong?</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri"><br>
</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri">I work with OSM Standard map in EPSG:3857 - WGS
84 / Pseudo-Mercator - projection and so are my shape files.</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri">Best regards,</font></div>
<div style="color: rgb(0, 0, 0); font-size: 12pt;"><font
face="Calibri">Herbert Faber</font> <br>
</div>
<div style="color: rgb(0, 0, 0); font-family:
Calibri,Helvetica,sans-serif; font-size: 12pt;">
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
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