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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi Nuno,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">As usual there are a number of ways to do this.
</span>Grass: r.resamp.stats <span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">
as Em suggested would work, but might I also suggest the <b>Warp</b> tool, based on
<b>gdal_warp</b>. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">This can be found by going to the
<b>Menu bar</b> select <b>Raster</b>, <b>Projections</b> and <b>Warp</b>.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Parameters:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Input Layer<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Set this to the Raster you want to resample<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Source/Target CRS
<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">If you’re not transforming your dataset to another CRS then you can leave these alone, but you can also set these to the value of the
Raster CRS<o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Resampling method to use<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">As you are looking for the average of the Pixel values, you can select
<b>Average</b> here.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">No Data value for output Bands:<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Set if required<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Output file resolution……:<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">This is the one of most interest to you, here you can set the resolution of the output to
<b>2500</b><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Reprojected:<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Specify the Location and Filename that you want the new Dataset to have, you can leave it blank if you like for a Temporary file to
be created.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hope this helps!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Kind Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Richard<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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——</span><br>
<span style="FONT-FAMILY: Arial, sans-serif; FONT-WEIGHT: bold; COLOR: #004d44">Richard McDonnell MSc GIS, FME Certified Professional</span><br>
<span style="FONT-FAMILY: Arial, sans-serif; COLOR: #004d44"><i>Flood Risk Management - Data Management</i></span><br>
<br>
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</span><br>
<span style="FONT-FAMILY: Arial, sans-serif; COLOR: #565148">Jonathan Swift Street, Trim, Co Meath, C15 NX36</span><br>
<span style="FONT-FAMILY: Arial, sans-serif; COLOR: #565148">——</span><br>
<span style="FONT-FAMILY: Arial, sans-serif; COLOR: #565148">M +353 87 688 5964 T +353 46 942 2409</span><br>
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<span style="FONT-FAMILY: Arial, sans-serif; COLOR: #004d44">——<br>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> QGIS-User <qgis-user-bounces@lists.osgeo.org>
<b>On Behalf Of </b>Emma Hain via QGIS-User<br>
<b>Sent:</b> 14 May 2024 02:20<br>
<b>To:</b> Nuno Manuel de Figueiredo de Santos Loureiro <nlourei@ualg.pt><br>
<b>Cc:</b> qgis-user@lists.osgeo.org<br>
<b>Subject:</b> Re: [Qgis-user] RASTER RESOLUTION REDUCING<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi Nuno<o:p></o:p></p>
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<p class="MsoNormal">Apologies in advance, I am no raster specialist, but perhaps try using some of the other tools such as Grass: r.resamp.stats<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">To get the information, would the <a href="https://docs.qgis.org/3.34/en/docs/user_manual/processing_algs/gdal/rastermiscellaneous.html#raster-information">
GDAL Raster Information tool</a> assist?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Cheers<o:p></o:p></p>
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<p class="MsoNormal">Em<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Tue, 7 May 2024 at 23:16, Nuno Manuel de Figueiredo de Santos Loureiro via QGIS-User <<a href="mailto:qgis-user@lists.osgeo.org">qgis-user@lists.osgeo.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Dear all,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">I need to reduce the resolution of a raster, from a 30 meter pixel to a 2500 meter pixel.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Performing this operation via "Creating new layers from an existing layer" and using the "Resolution" raster parameter is very easy.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">But the value of the new 2500 meter grids is not the average of the values of the 30 meter grids.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">How can I determine that in the destination grids its value is the average of the values in the original grids?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Suggestions will be very welcome!<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Grateful,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Nuno<o:p></o:p></span></p>
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<p class="MsoNormal">_______________________________________________<br>
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<br>
<span class="gmailsignatureprefix">-- </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Verdana",sans-serif;color:#444444">Emma Hain — Product Manager/Senior GIS Analyst<br>
<a href="mailto:emma@north-road.com" target="_blank"><span style="color:#4E8DAF;text-decoration:none">emma@north-road.com</span></a>
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<p class="MsoNormal"><b><span style="font-family:"Verdana",sans-serif;color:#444444">North Road</span></b><span style="font-family:"Verdana",sans-serif;color:#444444"><br>
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