This is a small program that calculates the Fourier transform of data describing the variability of the sea water level over time due to tides. It is best suited for processing data downloaded from https://tidesandcurrents.noaa.gov/
The purpose is to enable checking what are the dominant frequencies in the variability of the tides and seeing the well-known major tidal constituents (see https://en.wikipedia.org/wiki/Theory_of_tides#Tidal_constituents).