Uses frequency response and transfer function techniques with cross-spectral and fast Fourier transform methods to determine boundary values for computing the flow field of a coastal sea. Tide data containing considerable perturbations from swell and meteorological disturbances are analyzed. In computing frequency response, the effect of noise in the input is treated by a canceling technique and by the choice of a reference station to evaluate the interdependencies among the other stations at the boundary. The usefulness of the network frequency response function is threefold: (1) future conditions can be simulated using observed water levels at any single location, (2) boundary information for models of different grid size can be obtained by interpolation, and (3) missing data at a given location can be estimated optimally using data at neighboring stations and the network response function. The paper discusses an example of such an application, the determination of a boundary of a two-dimensional model of Jamaica Bay, NYC. (Presented at 14th International Conference on Coastal Engineering, Copenhagen, June 1974.) 17 pp. Ref.