draw.tree {maptree}R Documentation

Graph a Classification or Regression Tree

Description

Graph a classification or regression tree with a hierarchical tree diagram, optionally including colored symbols at leaves and additional info at intermediate nodes.

Usage

  draw.tree (tree, cex=par("cex"), pch=par("pch"), size=2.5*cex, 
      col=NULL, nodeinfo=FALSE, units="", cases="obs", 
      digits=getOption("digits"), print.levels=TRUE, 
      new=TRUE)

Arguments

tree object of class rpart or tree.
cex size of text, par parameter.
pch shape of symbol at leaves, par parameter.
size if size=0, draw terminal symbol at leaves else a symbol of size in cex units.
col vector of colors from hsv, rgb, etc, or if NULL, then use rainbow.
nodeinfo if TRUE, add a line at each node with mean value of response, number of observations, and percent deviance explained (or classified correct).
units label for units of mean value of response, if regression tree.
cases label for type of observations.
digits number of digits to round mean value of response, if regression tree.
print.levels if TRUE, print levels of factors at splits, otherwise only the factor name.
new if TRUE, call plot.new.

Details

As in plot.rpart(,uniform=TRUE), each level has constant depth. Specifying nodeinfo=TRUE, shows the deviance explained or the classification rate at each node.

A split is shown, for numerical variables, as variable <> value when the cases with lower values go left, or as variable >< value when the cases with lower values go right. When the splitting variable is a factor, and print.levels=TRUE, the split is shown as levels = factor = levels with the cases on the left having factor levels equal to those on the left of the factor name, and correspondingly for the right.

Value

The vector of colors supplied or generated.

Author(s)

Denis White, white.denis@epa.gov

See Also

rpart, tree, draw.clust, map.groups

Examples

  library (rpart)
  data (oregon.env.vars)

  draw.tree (clip.rpart (rpart (oregon.env.vars), best=7), 
      nodeinfo=TRUE, units="species", cases="cells", digits=0)

[Package maptree version 1.4-5 Index]