R: Pie Charts

pie {graphics} | R Documentation

## Pie Charts

### Description

Draw a pie chart.

### Usage

    pie(x, labels = names(x), edges = 200, radius = 0.8,
        clockwise = FALSE, init.angle = if(clockwise) 90 else 0,
        density = NULL, angle = 45, col = NULL, border = NULL,
        lty = NULL, main = NULL, ...)

### Arguments

`x` | a vector of non-negative numerical quantities. The values in `x` are displayed as the areas of pie slices.
`labels` | one or more expressions or character strings giving names for the slices. Other objects are coerced by `as.graphicsAnnot`. For empty or `NA` (after coercion to character) labels, no label nor pointing line is drawn.
`edges` | the circular outline of the pie is approximated by a polygon with this many edges.
`radius` | the pie is drawn centered in a square box whose sides range from -1 to 1. If the character strings labeling the slices are long it may be necessary to use a smaller radius.
`clockwise` | logical indicating if slices are drawn clockwise or counter clockwise (i.e., mathematically positive direction), the latter is default.
`init.angle` | number specifying the starting angle (in degrees) for the slices. Defaults to 0 (i.e., ‘3 o'clock’) unless `clockwise` is true where `init.angle` defaults to 90 (degrees), (i.e., ‘12 o'clock’).
`density` | the density of shading lines, in lines per inch. The default value of `NULL` means that no shading lines are drawn. Non-positive values of `density` also inhibit the drawing of shading lines.
`angle` | the slope of shading lines, given as an angle in degrees (counter-clockwise).
`col` | a vector of colors to be used in filling or shading the slices. If missing a set of 6 pastel colours is used, unless `density` is specified when `par("fg")` is used.
`border, lty` | (possibly vectors) arguments passed to `polygon` which draws each slice.
`main` | an overall title for the plot.
`...` | graphical parameters can be given as arguments to `pie`. They will affect the main title and labels only.

### Note

Pie charts are a very bad way of displaying information. The eye is good at judging linear measures and bad at judging relative areas. A bar chart or dot chart is a preferable way of displaying this type of data.

Cleveland (1985), page 264: “Data that can be shown by pie charts always can be shown by a dot chart. This means that judgements of position along a common scale can be made instead of the less accurate angle judgements.” This statement is based on the empirical investigations of Cleveland and McGill as well as investigations by perceptual psychologists.

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

Cleveland, W. S. (1985) The Elements of Graphing Data. Wadsworth: Monterey, CA, USA.

### See Also

`dotchart`.

### Examples

    require(grDevices)
    pie(rep(1, 24), col = rainbow(24), radius = 0.9)

    pie.sales <- c(0.12, 0.3, 0.26, 0.16, 0.04, 0.12)
    names(pie.sales) <- c("Blueberry", "Cherry",
        "Apple", "Boston Cream", "Other", "Vanilla Cream")
    pie(pie.sales) # default colours
    pie(pie.sales, col = c("purple", "violetred1", "green3",
                           "cornsilk", "cyan", "white"))
    pie(pie.sales, col = gray(seq(0.4, 1.0, length = 6)))
    pie(pie.sales, density = 10, angle = 15 + 10 * 1:6)
    pie(pie.sales, clockwise = TRUE, main = "pie(*, clockwise = TRUE)")
    segments(0, 0, 0, 1, col = "red", lwd = 2)
    text(0, 1, "init.angle = 90", col = "red")

    n <- 200
    pie(rep(1, n), labels = "", col = rainbow(n), border = NA,
        main = "pie(*, labels=\"\", col=rainbow(n), border=NA,..")

[Package graphics version 3.1.2 Index]