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<p>hopefully <a class="moz-txt-link-freetext" href="https://github.com/OSGeo/gdal/pull/7077">https://github.com/OSGeo/gdal/pull/7077</a> should answer
your question. You'll note subtle differences of behavior between
gdalwarp on one side and gdaladdo/gdal_translate on the other side</p>
<p>Even<br>
</p>
<div class="moz-cite-prefix">Le 16/01/2023 à 13:32, Laurențiu Nicola
via gdal-dev a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:e4578776-7185-4f76-a314-8f02c6688ee1@betaapp.fastmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title></title>
<style type="text/css">p.MsoNormal,p.MsoNoSpacing{margin:0}</style>
<div style="font-family:Arial;">PPS: Looks like some
experimentation is probably better than weeks of worrying :-).
It looks like the input no data values are actually not included
in the computation. But I'd still like to know how they are
handled, if that's possible.<br>
</div>
<div style="font-family:Arial;"><br>
</div>
<div style="font-family:Arial;">Laurentiu<br>
</div>
<div style="font-family:Arial;"><br>
</div>
<div>On Mon, Jan 16, 2023, at 14:05, Laurențiu Nicola via gdal-dev
wrote:<br>
</div>
<blockquote type="cite" id="qt" style="">
<div style="font-family:Arial;">PS:<br>
</div>
<div style="font-family:Arial;"><br>
</div>
<div>On Mon, Jan 16, 2023, at 13:58, Laurențiu Nicola wrote:<br>
</div>
<blockquote type="cite" id="qt-qt" style="">
<div style="font-family:Arial;"><br>
</div>
<ul>
<li style="font-family:Arial;">the <span class="qt-qt-font"
style="font-family:menlo, consolas, monospace,
sans-serif;"><span class="font"
style="font-family:menlo, consolas, monospace,
sans-serif;"><span class="qt-font"
style="font-family:menlo, consolas, monospace,
sans-serif;"><span class="font"
style="font-family:menlo, consolas, monospace,
sans-serif;"><code
style="border-top-color:rgb(204, 204,
204);border-top-style:solid;border-top-width:1px;border-right-color:rgb(204,
204,
204);border-right-style:solid;border-right-width:1px;border-bottom-color:rgb(204,
204,
204);border-bottom-style:solid;border-bottom-width:1px;border-left-color:rgb(204,
204,
204);border-left-style:solid;border-left-width:1px;border-image-outset:0;border-image-repeat:stretch;border-image-slice:100%;border-image-source:none;border-image-width:1;border-top-left-radius:3px;border-top-right-radius:3px;border-bottom-right-radius:3px;border-bottom-left-radius:3px;background-color:rgb(246,
246,
246);background-position-x:0%;background-position-y:0%;background-repeat:repeat;background-attachment:scroll;background-image:none;background-size:auto;background-origin:padding-box;background-clip:border-box;font-family:menlo,
consolas,
monospace;font-size:90%;padding-top:1px;padding-right:3px;padding-bottom:1px;padding-left:3px;">-srcnodata</code></span></span></span></span>
docs and <span class="qt-qt-font"
style="font-family:menlo, consolas, monospace,
sans-serif;"><span class="font"
style="font-family:menlo, consolas, monospace,
sans-serif;"><span class="qt-font"
style="font-family:menlo, consolas, monospace,
sans-serif;"><span class="font"
style="font-family:menlo, consolas, monospace,
sans-serif;"><code
style="border-top-color:rgb(204, 204,
204);border-top-style:solid;border-top-width:1px;border-right-color:rgb(204,
204,
204);border-right-style:solid;border-right-width:1px;border-bottom-color:rgb(204,
204,
204);border-bottom-style:solid;border-bottom-width:1px;border-left-color:rgb(204,
204,
204);border-left-style:solid;border-left-width:1px;border-image-outset:0;border-image-repeat:stretch;border-image-slice:100%;border-image-source:none;border-image-width:1;border-top-left-radius:3px;border-top-right-radius:3px;border-bottom-right-radius:3px;border-bottom-left-radius:3px;background-color:rgb(246,
246,
246);background-position-x:0%;background-position-y:0%;background-repeat:repeat;background-attachment:scroll;background-image:none;background-size:auto;background-origin:padding-box;background-clip:border-box;font-family:menlo,
consolas,
monospace;font-size:90%;padding-top:1px;padding-right:3px;padding-bottom:1px;padding-left:3px;">gdalwarpkernel.cpp</code></span></span></span></span>
suggest that masked pixels are not included in the
computation (unlike those of no data?)<br>
</li>
</ul>
</blockquote>
<div style="font-family:Arial;">The remark in the brackets is
wrong, of course, since the docs are specifically about <code
style="border-top-color:rgb(204, 204,
204);border-top-style:solid;border-top-width:1px;border-right-color:rgb(204,
204,
204);border-right-style:solid;border-right-width:1px;border-bottom-color:rgb(204,
204,
204);border-bottom-style:solid;border-bottom-width:1px;border-left-color:rgb(204,
204,
204);border-left-style:solid;border-left-width:1px;border-image-outset:0;border-image-repeat:stretch;border-image-slice:100%;border-image-source:none;border-image-width:1;border-top-left-radius:3px;border-top-right-radius:3px;border-bottom-right-radius:3px;border-bottom-left-radius:3px;background-color:rgb(246,
246,
246);background-position-x:0%;background-position-y:0%;background-repeat:repeat;background-attachment:scroll;background-image:none;background-size:auto;background-origin:padding-box;background-clip:border-box;font-family:menlo,
consolas,
monospace;font-size:90%;padding-top:1px;padding-right:3px;padding-bottom:1px;padding-left:3px;">-srcnodata</code>
. But I'm still unsure how these are handled in the code. I
probably missed something, but I saw <a
href="https://github.com/OSGeo/gdal/blob/master/alg/gdalwarpkernel.cpp#L1225"
moz-do-not-send="true">the checks</a> for a mask, but not no
data.<br>
</div>
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</div>
</blockquote>
<div style="font-family:Arial;"><br>
</div>
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