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Polar Coordinates with Enhanced Controls

Source: R/ggplot-coord-circle.R
coord_circle.Rd

An extended version of coord_radial(), providing additional customization options.

Usage

coord_circle(
  theta = "x",
  start = 0,
  end = NULL,
  thetalim = NULL,
  rlim = NULL,
  expand = FALSE,
  direction = 1,
  clip = "off",
  r.axis.inside = NULL,
  rotate.angle = FALSE,
  inner.radius = 0,
  outer.radius = 0.95
)

Arguments

theta

variable to map angle to (x or y)

start

Offset of starting point from 12 o'clock in radians. Offset is applied clockwise or anticlockwise depending on value of direction.

end

Position from 12 o'clock in radians where plot ends, to allow for partial polar coordinates. The default, NULL, is set to start + 2 * pi.

thetalim, rlim

Limits for the theta and r axes.

expand

If TRUE, the default, adds a small expansion factor to the limits to prevent overlap between data and axes. If FALSE, limits are taken directly from the scale.

direction

1, clockwise; -1, anticlockwise

clip

Should drawing be clipped to the extent of the plot panel? A setting of "on" (the default) means yes, and a setting of "off" means no. For details, please see coord_cartesian().

r.axis.inside

One of the following:

  • NULL (default) places the axis next to the panel if start and end arguments form a full circle and inside the panel otherwise.

  • TRUE to place the radius axis inside the panel.

  • FALSE to place the radius axis next to the panel.

  • A numeric value, setting a theta axis value at which the axis should be placed inside the panel. Can be given as a length 2 vector to control primary and secondary axis placement separately.

rotate.angle

If TRUE, transforms the angle aesthetic in data in accordance with the computed theta position. If FALSE (default), no such transformation is performed. Can be useful to rotate text geoms in alignment with the coordinates.

inner.radius

A numeric in [0, 1) indicates the inner radius.

outer.radius

A numeric in (0, 1] indicates the outer radius. coord_radial() by default uses 0.8.

Examples

ggplot(mtcars, aes(disp, mpg)) +
    geom_point() +
    coord_circle(
        start = -0.4 * pi, end = 0.4 * pi,
        inner.radius = 0.3, outer.radius = 1
    )

ggplot(mtcars, aes(disp, mpg)) +
    geom_point() +
    coord_circle(
        start = -0.4 * pi, end = 0.4 * pi,
        inner.radius = 0.3, outer.radius = 0.5
    )