Ghid Karam

Hello, i hope you are all well. I am actually struggling with finding any info on the "compare to flat terrain" raster that can be created in the potential incoming solar radiation processing. What does the pixel value represent? is it the ratio between the total radiation generated with the DEM to the total radiation received by a flat terrain delimited by the same grid ? if so,is it possible ti generate the raster correponding to the actual values of radiation received by the flat terrain? Thank...