Tidal Constituents

PyFES provides two catalogues of tidal constituents, one for each prediction engine. Every constituent is characterised by its name, angular speed (in degrees per hour), and XDO notation encoding.

• Darwin catalogue — 99 constituents used by the FES/Darwin engine (engine: darwin). See DARWIN.

• Doodson catalogue — 80 constituents used by the PERTH/Doodson engine (engine: perth). See DOODSON.

For background on how constituent frequencies are derived from the six fundamental variables, see Harmonic Development and the Doodson Classification. For a comparison of the two engines, see Prediction Engines.