Place a

Places a "break" mark on an axis on an existing plot.

axis.break(axis=1,breakpos=NULL,pos=NULL,bgcol="white",breakcol="black",
  style="slash",brw=0.02)

Arguments

axis: which axis to break
breakpos: where to place the break in user units
pos: position of the axis (see axis).
bgcol: the color of the plot background
breakcol: the color of the "break" marker
style: Either gap, slash or zigzag
brw: break width relative to plot width

Value

nil

Details

The pos argument is not needed unless the user has specified a different position from the default for the axis to be broken.

Note

There is some controversy about the propriety of using discontinuous coordinates for plotting, and thus axis breaks. Discontinuous coordinates allow widely separated groups of values or outliers to appear without devoting too much of the plot to empty space. The major objection seems to be that the reader will be misled by assuming continuous coordinates. The gap style that clearly separates the two sections of the plot is probably best for avoiding this.

Author

Jim Lemon and Ben Bolker

Examples

 plot(3:10, main = "Axis break test")
 # put a break at the default axis and position
 axis.break()
 axis.break(2, 2.9, style = "zigzag")

 twogrp <- c(rnorm(10) + 4, rnorm(10) + 20)
 gap.plot(twogrp,gap = c(8,16), xlab = "Index", ylab = "Group values",
  main = "Two separated groups with gap axis break",
  col = c(rep(2, 10), rep(3, 10)), ytics = c(3, 5, 18, 20))
 legend(12, 6, c("Low group", "High group"), pch = 1, col = 2:3)