Plot Circular Plot

This visualising scheme represents the unidirectional relationship between the rows and the columns of a contingency table. 

PlotCirc(tab, acol = rainbow(sum(dim(tab))), aborder = "darkgrey",
         rcol = SetAlpha(acol[1:nrow(tab)], 0.5), rborder = "darkgrey",
         gap = 5, main = "", labels = NULL, cex.lab = 1.0, las = 1,
         adj = NULL, dist = 2)

Arguments

tab

a table to be visualised.

acol

the colors for the peripheral annuli.

aborder

the border colors for the peripheral annuli.

rcol

the colors for the ribbons.

rborder

the border colors for the ribbons.

gap

the gap between the entities in degrees.

main

the main title, defaults to "".

labels

the labels. Defaults to the column names and rownames of the table.

las

alignment of the labels, 1 means horizontal, 2 radial and 3 vertical.

adj

adjustments for the labels. (Left: 0, Right: 1, Mid: 0.5)

dist

gives the distance of the labels from the outer circle. Default is 2.

cex.lab

the character extension for the labels.

Details

The visual scheme of representing relationships can be applied to a table, given the observation that a table cell is a relationship (with a value) between a row and column. By representing the row and columns as segments along the circle, the information in the corresponding cell can be encoded as a link between the segments. In general, the cell represents a unidirectional relationship (e.g. row->column) - in this relationship the role of the segments is not interchangeable (e.g. (row,col) and (col,row) are different cells). To identify the role of the segment, as a row or column, the ribbon is made to terminate at the row segment but slightly away from the column segment. In this way, for a given ribbon, it is easy to identify which segment is the row and which is the column.

Value

the calculated points for the labels, which can be used to place userdefined labels.

Author

Andri Signorell <andri@signorell.net>

See also

PlotPolar

Examples

tab <- matrix(c(2,5,8,3,10,12,5,7,15), nrow=3, byrow=FALSE)
dimnames(tab) <- list(c("A","B","C"), c("D","E","F"))
tab
#>   D  E  F
#> A 2  3  5
#> B 5 10  7
#> C 8 12 15


PlotCirc( tab,
  acol = c("dodgerblue","seagreen2","limegreen","olivedrab2","goldenrod2","tomato2"),
  rcol = SetAlpha(c("red","orange","olivedrab1"), 0.5)
)


tab <- table(d.pizza$weekday, d.pizza$operator)
par(mfrow=c(1,2))
PlotCirc(tab, main="weekday ~ operator")
PlotCirc(t(tab), main="operator ~ weekday")