According to the Iran Department of Environment guideline
about the safe distances to landfill sites, the buffer zones were
determined for each layer and these buffered areas were ignored
by the study. The exclusion of certain unsuitable areas was done
by mask operation. To prepare a mask of unsuitable areas, all data
layers were multiplied by 0 so that if any pixel had a value of 0
coming from any layer, then the value of that pixel would become
0, meaning that the pixel was completely unsuitable as a landfill
site (Sener et al., 2006).