In QGIS, I would like to save a WMS layer representing the pHx10(ranging from 0 to 140 https://maps.isric.org/mapserv?map=/map/phh2o.map from ISRIC) using an area in Belgium as a map extent.
I saved the WMS layer using "save as", GeoTIFF as format, resolution of 1m and the selected map extent. At first, the output really looks like a part of the WMS layer which is what I want. However, the values of the raster are divided into bands Red, Green and Blue, each of them having different values. When I perform a classification on the results, it gives totally different values from the WMS layer and I can not tell wich bands represents the pH and why the result is divided in 3 bands.
The first picture represents the WMS layer with normal pHx10 values. The second image is the saved raster with the right color but with the 3 bands (test_pH layer). The third picture is result of the classification when I use band 2 for example (values outranging pHx10 values).
How can I get a raster with the right pH values corresponding to the color/range of picture 1 and 2?