0 0 RESERVED
1 1 THIN DENSITY SWARM (SWARM VISIBLE ONLY WHEN NEAR ENOUGH FOR INDIVIDUAL LOCUSTS TO BE DISCERNED)
2 2 MEDIUM DENSITY SWARM
3 3 DENSE SWARM (OBSCURING NEARBY FEATURES, E.G. TREES)
4 4 ISOLATED HOPPERS SEEN SINGLY
5 5 SCATTERED HOPPERS, SEVERAL VISIBLE SIMULTANEOUSLY
15 15 MISSING VALUE
