Level I: the V index is less than 0.005. At this level when the V index is increasing, the minimum mangrove band width decreases rapidly quickly from 600 m to 240 m.
– Level II: the V index ranges from 0.005 to 0.015. At this level, an increase in the V index causes the minimum band width to decrease fairly quickly from 240 m to 120 m.
– Level III: the V index is from 0.010 to 0.015. At this level, an increase in the V index results in a gradual decrease in the minimum band width from 120 m to 80 m.
– Level IV: the V index lies between 0.015 and 0.028. An increase in the V index at this level results in a slow decrease in the minimum band width from 40 m to 80 m.