identifying a deviation from the intermediate point to a new intermediate point such that the new intermediate point has a cumulative threat risk value lower than or equal to {HEAD ~ the allowable threat risk} per {TAIL ~ grid cell} 
per
identifying a deviation from the intermediate point to a new intermediate point such that the new intermediate point has a cumulative threat risk value lower than or equal to { HEAD ~ the allowable threat risk } per { TAIL ~ grid cell }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL