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NON CLASSIFIÉ / UNCLASSIFIED<br>
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<p class="MsoNormal"><span lang="EN-CA">Hello to the QGIS user’s community, <o:p>
</o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">I’m a planetary scientist working for the Canadian Space Agency who is working with lunar south pole data. I’m struggling with an issue when running a simple multiplication raster calculation that I’ve included below
(sorry for vague layer names, data is not public):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">“Layer1” * “Layer2” * “Layer3” * “Layer4” * “Layer5” * “Layer6”<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">The output raster is set to the spatial resolution of the highest resolution layer, as I’m trying to gather contextual data from coarser datasets at very specific locations.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Most cells are calculated correctly, but many cells (<10-20%) are miscalculated to the tune of 10-30% of the expected value (sometime values are calculated lower than they should be, sometimes higher. Even when the highest
spatial resolution cell is fully contained within a single cell in all other layers (no overlapping cell boundaries that might lead to different resampling values under a nearest neighbour protocol), the calculated value can still be incorrect.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">I’m running QGIS 3.44.7, my system is using an i7-1265U with 32 gb of ram. The rasters are large, 5000x5000 cell 32-bit float Geotiffs. All are using the same coordinate system (ESRI:103878 - Moon_2000_South_Pole_Stereographic).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">I’ve exported the input layers so I can run the same calculation in ArcPro, and the cells are all calculated correctly. Not sure if that helps narrow down the issue.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Cheers, <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">James<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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