I have soil map with 3 RGB bands and I need a zonal histogram for polygons from this raster (how many pixels of each soil the polygon contains).
First I tried to sieve the raster and then get zonal histogram, but I found that sieve tool by default uses first band (red in my case). So different colors with the same value in the red band get the same value after the sieve. I tried this with another band but result was the same. Also I tried to create raster layer with raster calculator (just sum over values from all 3 bands).
Can anybody recommend any solution using QGIS?