Display distributions as dendrites

Display the distributions of one or more sets of points as branching (dendritic) clusters.

Usage

dendroPlot(x,breaks=list(10,10,10),pch=1,col=par("fg"),cex=1,nudge=NA,
  setlabels=NA,...)

Arguments

x: A list or data frame of numeric or factor or character columns.
breaks: A list of cutpoints to transform numeric values into factors (see cut). Must be at least one number >= 2.
pch: Symbol(s) to use in plotting the values.
col: Color(s) for the symbols.
cex: Size of the symbol(s) to use in plotting.
nudge: The amount to set each consecutive value in a category away from the center of the dendrite.
setlabels: Labels to place along the abcissa to identify the sets.
...: Other arguments passed to plot.

Details

dendroPlot displays the distributions of categorical values as stacks of "branches". The lengths of the branches show the number of values in each category, rather like the opposed bars in a pyramid plot, except that there is no separation of groups. The distribution of numeric values can also be displayed by passing a set of breakpoints to categorize the values. The breakpoints will usually be equidistant, but unevenly spaced breakpoints can be passed. If an element of x is numeric, the values of the corresponding x element will be used to place the points, but the branches will be defined as the categories formed by applying the breaks to those numeric values.

Note that in the first example, the breakpoints for the first and third elements are used to define the ten branches for each. The second element of x is already categorical, so the breakpoints are ignored. When comparing distributions with very different ranges it may be necessary to adjust the breakpoints to get a satisfactory result.

Each successive point in a category is nudged away from the center of the dendrite. If nudge has more than one value, the points will be nudged up and down for categorical variables to enable closer packing. The second value of nudge is ignored for numeric variables. The aspect ratio of the plot, the character expansion and the nudging will have to be adjusted to give the best point spacing for most dendroPlots.

Note

The ehplot function is a much more versatile instantiation of this type of plot. dendroPlot has been retained as there are currently a few differences that some users may find valuable. However, it is not impossible that dendroPlot will disappear in the future. Another very useful version of this type of plot is beeswarm in the beeswarm package.

Value

nil

Author

Jim Lemon

Examples

 x<-list(runif(90,1,3),factor(sample(LETTERS[1:10],100,TRUE)),rnorm(80,mean=5))
 dendroPlot(x,xlab="Groups",ylab="Value of x",main="Test dendroPlot I")

 # now apply a nudge factor and different breaks
 dendroPlot(x,breaks=list(8,10,10),nudge=c(0.05,0.1),
  xlab="Groups",ylab="Value of x",main="Test dendroPlot II")