Nadir
-----

The SWOT simulator can be used to generate any nadir like observation. The
mission :py:const:`ephemeris <settings.ephemeris>` should be provided as
explained in Generation of the SWOT grid section. The corresponding
:py:const:`cycle_duration <settings.cycle_duration>` and the
:py:const:`height <settings.height>` of the satellite value should be
specified. Default values are for the SWOT mission:

* ``cycle_duration=20.86455`` days
* ``height=891000`` m