3.25.57 polar

The ‘set polar‘ command changes the meaning of the plot from rectangular coordinates to polar coordinates.

Syntax:

      set polar
      unset polar
      show polar

In polar coordinates, the dummy variable (t) is an angle. The default range of t is [0:2*pi], or, if degree units have been selected, to [0:360] (see angles).

The command ‘unset polar‘ changes the meaning of the plot back to the default rectangular coordinate system.

The ‘set polar‘ command is not supported for ‘splot‘s. See the mapping command for similar functionality for ‘splot‘s.

While in polar coordinates the meaning of an expression in t is really r = f(t), where t is an angle of rotation. The trange controls the domain (the angle) of the function. The r, x and y ranges control the extent of the graph in the x and y directions. Each of these ranges, as well as the rrange, may be autoscaled or set explicitly. For details, see rrange and xrange.

Example:

      set polar
      plot t*sin(t)
      set trange [-2*pi:2*pi]
      set rrange [0:3]
      plot t*sin(t)

The first ‘plot‘ uses the default polar angular domain of 0 to 2*pi. The radius and the size of the graph are scaled automatically. The second ‘plot‘ expands the domain, and restricts the size of the graph to the area within 3 units of the origin. This has the effect of limiting x and y to [-3:3].

You may want to ‘set size square‘ to have ‘gnuplot‘ try to make the aspect ratio equal to unity, so that circles look circular. See also polar demos (polar.dem) and polar data plot (poldat.dem).

This document was generated on April 4, 2012 using texi2html 5.0.