The overall factor rating was based on the multiplication (C x D x F x
L x P) on which each layer was assigned a value ranging from 1 for
S1 to 0.2 for N. These values were then multiplied and used for
identifying the risk area. The upper limits of values for S1, S2, S3
and N were (1) 5, (0.6) 5, (0.4) 5 and (0.2) 5 respectively (Table 4.).