2.21.52 polar

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

Syntax:

      set polar
      unset polar
      show polar

There have been changes made to polar mode in version 3.7, so that scripts for `gnuplot` versions 3.5 and earlier will require modification. The main change is that the dummy variable t is used for the angle so that the x and y ranges can be controlled independently. Other changes are: 1) tics are no longer put along the zero axes automatically —use `set xtics axis nomirror`; `set ytics axis nomirror`; 2) the grid, if selected, is not automatically polar —use `set grid polar`; 3) the grid is not labelled with angles —use label as necessary.

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, and the x and y ranges control the range of the graph in the x and y directions. Each of these ranges, as well as the rrange, may be autoscaled or set explicitly. See xrange for details of all the ranges commands.

Example:

      set polar
      plot t*sin(t)
      plot [-2*pi:2*pi] [-3:3] [-3:3] 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 [-3:3] in both directions.

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).