Construction of KP solitons from wave patterns

We often observe that waves on the surface of shallow water form complex web-like patterns. They are examples of nonlinear waves, and these patterns are generated by nonlinear interactions among several obliquely propagating waves. In this note, we discuss how to construct an exact soliton solution of the KP equation from a web-pattern of shallow water wave. This can be regarded as an ` inverse problem' in the sense that by measuring certain metric data of the solitary waves in the given pattern, it is possible to construct an exact KP soliton solution which can describe the non-stationary dynamics of the pattern.