By default, GNUPLOT assumes the independent variable in polar plots
is in units of radians. If set angles degrees is specified before
set polar then the default range is [0:360] and the independent
variable has units of degrees. This is particularly useful for
plots of data files. The angle setting also hold for the 3-d
mapping as set via the set mapping command.
Syntax:
set angles { degrees | radians }
show angles