PyRsw: Python rotating shallow water model. PyRsw is a python solver of the Rotating Shallow Water Model. This is an approximate model that can be derived from the full Bossinessq equations in the limit of constant density and strictly hydrostatic motions. It is more general than the one-layer quasigeostrophic model in that it allows for variable Rossby numbers and can include gravity waves. It is a useful model to study the oceans, the atmosphere and other planetary systems as well.