Yeah the moment you reach for pixel level processing tricks in GIS you need to pause and rtfm. Grade calculations are right in qgis docs and part of their less

Yeah the moment you reach for pixel level processing tricks in GIS you need to pause and rtfm. Grade calculations are right in qgis docs and part of their lessons, and are also top Google hits. https://docs.qgis.org/3.40/en/docs/training_manual/rasters/terrain_analysis.html https://docs.qgis.org/3.40/en/docs/training_manual/rasters/t... Even better, you'll learn about DEMs vs topo maps.