The graph below displays the ground pattern from a constant flow tank at a rate of 418 gallons per second which falls into the coverage level 4 category according to the recommended coverage level chart below. The plot shows coverage level 4 in red expressed in gallons per hundred square feet (gpc) nested inside coverage level 2. The 4 is not continuous and does not occur outside the main pattern. The length of the 4 gpc line (253 feet) is typically expressed as the sum of the individual islands of 4 gpc. Differences in tank and gating systems and drop conditions may produce more or fewer islands of a specific coverage level.