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<p>Bill,</p>
<p>here you upsample from a 3x3 to a 5x5 array. Consequently each
target pixel averages 5/3 x 5/3 contributing source pixels , not 2
x 2. This way the total sum of the values of the target array is
preserved compared to to the sum of the values of the source
array, if you multiply the sum by 3/5 * 3/5.</p>
<p>To get what you expect you should work with even-sized arrays</p>
<p>Even<br>
</p>
<div class="moz-cite-prefix">Le 27/09/2023 à 19:44, Bill Myers via
gdal-dev a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:CAA6+mXW5Obj1W1G7ZVFtwcoRXMhiZYDvvH16GKCwy27RD=h-2g@mail.gmail.com">
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<div>Hi,
<div>I am new to working with GDAL. We are trying to spatially
interpolate Numerical Weather Prediction (NWP) model data to
an arbitrary location, i.e. lat/lon. We have been using
gdal_translate but have been getting unexpected results. </div>
<div>We have used the resampling method called "average". In
this toy example, we are trying to resample to a grid with
twice the density of the input data set. As can be seen in
the image in the link below, the values at the points that
match the input points agree with the input values. That's
good. However, the interpolated values do not match our
expectations. We would expect the interpolated value at the
midpoint (directly between two input points) to be the
average of those two input points. As can be seen, this is
not the case.</div>
<div>Can someone please help us understand what we might be
doing incorrectly? Also, does GDAL have the functionality
that we are looking for?</div>
<div>Thanks for your help.</div>
<font color="#888888">
<div>-b</div>
</font></div>
<a href="https://pasteboard.co/uumLD4JtNmp3.png"
moz-do-not-send="true" class="moz-txt-link-freetext">https://pasteboard.co/uumLD4JtNmp3.png</a><br>
</div>
<br>
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</blockquote>
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My software is free, but my time generally not.</pre>
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