A cumulative threat risk value for each of {HEAD ~ the grid cells} is calculated, and an allowable threat risk per grid cell is established based on {TAIL ~ a rule} set 
A cumulative threat risk value for each of { HEAD ~ the grid cells } is calculated , and an allowable threat risk per grid cell is established based on { TAIL ~ a rule } set
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH