Hi Nuno, As usual there are a number of ways to do this. Grass: r.resamp.stats as Em suggested would work, but might I also suggest the Warp tool, based on gdal_warp. This can be found by going to the Menu bar select Raster, Projections and Warp.
Parameters: Input Layer Set this to the Raster you want to resample Source/Target CRS 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 Resampling method to use As you are looking for the average of the Pixel values, you can select Average here. No Data value for output Bands: Set if required Output file resolution……: This is the one of most interest to you, here you can set the resolution of the output to 2500 Reprojected: 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. Hope this helps! Kind Regards, Richard —— Richard McDonnell MSc GIS, FME Certified Professional Flood Risk Management - Data Management —— Oifig na nOibreacha Poiblí Office of Public Works Sráid Jonathan Swift, Baile Átha Troim, Co na Mí, C15 NX36 Jonathan Swift Street, Trim, Co Meath, C15 NX36 —— M +353 87 688 5964 T +353 46 942 2409 https://gov.ie/opw —— To send me files larger than 30MB, please use the link below https://filetransfer.opw.ie/filedrop/richard.mcdonn...@opw.ie Email Disclaimer: https://www.gov.ie/en/organisation-information/439daf-email-disclaimer/ From: QGIS-User <qgis-user-boun...@lists.osgeo.org> On Behalf Of Emma Hain via QGIS-User Sent: 14 May 2024 02:20 To: Nuno Manuel de Figueiredo de Santos Loureiro <nlou...@ualg.pt> Cc: qgis-user@lists.osgeo.org Subject: Re: [Qgis-user] RASTER RESOLUTION REDUCING Hi Nuno Apologies in advance, I am no raster specialist, but perhaps try using some of the other tools such as Grass: r.resamp.stats To get the information, would the GDAL Raster Information tool<https://docs.qgis.org/3.34/en/docs/user_manual/processing_algs/gdal/rastermiscellaneous.html#raster-information> assist? Cheers Em On Tue, 7 May 2024 at 23:16, Nuno Manuel de Figueiredo de Santos Loureiro via QGIS-User <qgis-user@lists.osgeo.org<mailto:qgis-user@lists.osgeo.org>> wrote: Dear all, I need to reduce the resolution of a raster, from a 30 meter pixel to a 2500 meter pixel. Performing this operation via "Creating new layers from an existing layer" and using the "Resolution" raster parameter is very easy. But the value of the new 2500 meter grids is not the average of the values of the 30 meter grids. How can I determine that in the destination grids its value is the average of the values in the original grids? Suggestions will be very welcome! Grateful, Nuno _______________________________________________ QGIS-User mailing list QGIS-User@lists.osgeo.org<mailto:QGIS-User@lists.osgeo.org> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user -- Emma Hain — Product Manager/Senior GIS Analyst e...@north-road.com<mailto:e...@north-road.com> [https://north-road.com] North Road Cartography • Development • Spatial Analysis ________________________________ north-road.com<http://north-road.com> [https://ci3.googleusercontent.com/mail-sig/AIorK4xbsQ72BNIM2cWMZcuEKVer1Bwaq_gqYkdbtrjK2ifrqv-4o7aWjcvilgYXtNGpXLNgD00xgmQ]<https://twitter.com/northroadgeo>[https://ci3.googleusercontent.com/mail-sig/AIorK4zEBWGJKio8gqmFT0h_51t4ZnmoGgbmV7SeL-4FKvwWApFWDWyK7p-c0-cSskUe7pjQzjEZj9Q]<https://www.linkedin.com/company/north-road-studios>[https://ci3.googleusercontent.com/mail-sig/AIorK4wlMciFPm8hqQZB_Qi57PUCv1dJqUC1A2i9qEMzWRFLcJ7Jil30YnULdJLxT6-qMfI6J4kcac4]<https://www.facebook.com/North-Road-997236690392419/home>
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