I am pretty new to QGIS. I have a .tif file (Land-Ocean mask) with a high spatial resolution (150m) on a global scale. I would like to first resize it to 0.25-degree spatial resolution, and then calculate the number of those pixels/grids from the high-resolution layer (150m), that fall within the pixels of the coarser spatial resolution layer (0.25-degree). The values of the Land-Ocean mask are defined as 0/1 for Ocean and Land.
I think for the resizing/resampling if right-click on the raster layer then
Export > save as, and from there changing the
Resolution to 0.25 would be the case to have the coarser layer.
If I am right, how do I count/sum the number of those pixels as a new layer?