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Circular Chord Diagram

Source: R/plotCirc.R
plotCirc.Rd

Draws a chord diagram of a two-way table: the categories of the rows lie as sectors on the right half of a circle, those of the columns on the left half, and every cell of the table is a ribbon between its row and its column sector whose width is proportional to its value.

Usage

plotCirc(
  x,
  main = NULL,
  gap = 3,
  opacity = 0.5,
  sector = TRUE,
  ribbon = TRUE,
  labels = TRUE,
  stamp = .useTheme,
  ...
)

Arguments

x

a numeric matrix or two-way table with non-negative entries. Rows and columns are the two sets of categories; the dimnames give the labels.

main

main title. NULL (default) draws none, unless the theme sets autoTitle = TRUE (see theme); the title is then the name of x. "", NA or FALSE always suppress it and compact the top margin; any other string is used as given.

gap

gap between two sectors, in degrees.

opacity

opacity of the default ribbon colors, between 0 and 1.

sector

sector styling. Can be:

  • TRUE (default): the qualitative palette of the active theme (see theme), without border,

  • FALSE or NULL: no sectors,

  • a vector of colors,

  • a list with the elements col and/or border.

Colors are given for the rows followed by the columns of x and are recycled to their number.

ribbon

ribbon styling. Can be:

  • TRUE (default): the color of the row sector a ribbon starts from, with the opacity opacity, without border,

  • FALSE or NULL: no ribbons,

  • a vector of colors, one per row of x (recycled),

  • a list with the elements col and/or border.

labels

label styling. Can be:

  • TRUE (default): the row and column names of x, written horizontally,

  • FALSE or NULL: no labels,

  • a character vector of labels, for the rows followed by the columns of x,

  • a list with the elements labels, cex, col and las; las = 2 writes the labels radially, perpendicular to the circle.

stamp

controls the corner stamp. .useTheme (default) resolves to getTheme()$stamp. TRUE/FALSE/ NULL, a string, or a named list for stamp().

...

further graphical parameters passed to par() via the internal framework.

Value

Invisibly, a list with the data frame sectors (category, margin ("row" or "col"), total, start and end angle in radians, color) and the label positions x and y.

Details

The size of a sector is the margin total of its category. Within a row sector the ribbons are ordered like the column sectors they lead to, within a column sector like the row sectors, both from top to bottom; this keeps crossings few. Empty cells draw no ribbon.

The plot region is enlarged as far as needed for the labels, so that long category names are not cut off.

See also

Other plot.special: plotBinaryTree(), plotLift(), plotMiss(), plotPolar(), plotPropCI(), plotSankey(), plotTernary(), plotTimeSeries(), plotTreemap(), plotWeb()

Examples

set.seed(1)
x <- matrix(sample(1:10, 36, replace = TRUE), nrow = 6,
            dimnames = list(LETTERS[1:6], letters[1:6]))

plotCirc(x)


# a contingency table, radial labels
plotCirc(HairEyeColor[, , "Female"], labels = list(las = 2))


# own colors and white borders
plotCirc(x,
         sector = list(col = hcol(), border = "white"),
         ribbon = list(border = "white"))