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Circular Chord Diagram

Source: R/plotCirc.R
plotCirc.Rd

Draws a circular chord diagram from a matrix, showing flows between rows and columns using sectors and ribbons. The plot is rendered using base graphics and supports flexible styling via object-based arguments.

Usage

plotCirc(
  x,
  sector = TRUE,
  ribbon = TRUE,
  labels = TRUE,
  gap = 5,
  main = NULL,
  ...
)

Arguments

x

A numeric matrix. Rows and columns define the connections between sectors.

sector

sector styling. Can be:

  • a logical (TRUE/FALSE) to enable/disable sectors,

  • a vector of colors,

  • or a list with elements col and border.

Colors are recycled to match the number of sectors (nrow(x) + ncol(x)).

ribbon

ribbon styling. Can be:

  • a logical (TRUE/FALSE) to enable/disable ribbons,

  • a vector of colors,

  • or a list with elements col and border.

Colors are recycled to match the number of row categories (nrow(x)).

labels

label styling. Can be:

  • a logical (TRUE/FALSE) to enable/disable labels,

  • a character vector of labels,

  • or a list with parameters passed to internal label drawing.

gap

numeric. Gap between sectors in degrees.

main

character. Main title of the plot.

...

additional graphical parameters passed to internal plotting functions.

Value

Invisibly returns a list with label positions:

x

x-coordinates of labels

y

y-coordinates of labels

Details

The function constructs a circular layout where:

  • Columns of x are placed on one half of the circle

  • Rows of x are placed on the opposite half

  • Ribbon widths are proportional to matrix entries

Sector sizes correspond to marginal sums of the matrix.

Internally, angles are computed in radians and mapped to Cartesian coordinates.

See also

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

Examples

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

plotCirc(x)


# Custom colors
plotCirc(
  x,
  sector = list(col = rainbow(12), border = "grey50"),
  ribbon = list(col = rainbow(6), border = NA)
)
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character
#> Warning: supplied color is neither numeric nor character


# Custom labels
plotCirc(
  x,
  labels = list(cex = 0.8, col = "blue", las = 2)
)