The meaning of this Cartesian product would be to relate the rain gauge’s prediction of large storms to the actual pond performance during rain events. Higher values indicate designs and station information that could model and control flooding in a reasonable way. Lower relative values may indicate a design problem or a nonrepresentative gauge location. To illustrate composition for the same situation, let us try to determine if the rainstorms are widespread or localized. Let us compare the results from a pond system well removed from the previous location during the same storm.