3.25.1 angles

By default, ‘gnuplot‘ assumes the independent variable in polar graphs 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 applies to 3D mapping as set via the mapping command.

Syntax:

      set angles {degrees | radians}
      show angles

The angle specified in ‘set grid polar‘ is also read and displayed in the units specified by angles.

angles also affects the arguments of the machine-defined functions sin(x), cos(x) and tan(x), and the outputs of asin(x), acos(x), atan(x), atan2(x), and arg(x). It has no effect on the arguments of hyperbolic functions or Bessel functions. However, the output arguments of inverse hyperbolic functions of complex arguments are affected; if these functions are used, ‘set angles radians‘ must be in effect to maintain consistency between input and output arguments.

      x={1.0,0.1}
      set angles radians
      y=sinh(x)
      print y         #prints {1.16933, 0.154051}
      print asinh(y)  #prints {1.0, 0.1}

but

      set angles degrees
      y=sinh(x)
      print y         #prints {1.16933, 0.154051}
      print asinh(y)  #prints {57.29578, 5.729578}

See also poldat.dem: polar plot using angles demo.

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