ggdendro: dendro_data.tree – R documentation

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dendro_data.tree

Extract data from regression tree object for plotting using ggplot.

Description

Extracts data to plot line segments and labels from a tree::tree() object. This data can then be manipulated or plotted, e.g. using ggplot2::ggplot().

Usage

## S3 method for class 'tree'
dendro_data(model, type = c("proportional", "uniform"), ...)

Arguments

`model`	object of class "tree", e.g. the output of tree()
`type`	Either `proportional` or `uniform`. If this partially matches "uniform", the branches are of uniform length. Otherwise they are proportional to the decrease in impurity.
`...`	ignored

Value

A list of three data frames:

`segments`	a data frame containing the line segment data
`labels`	a data frame containing the label text data
`leaf_labels`	a data frame containing the leaf label text data

Author(s)

Andrie de Vries, using code modified from original by Brian Ripley

Examples

### Demonstrate tree

if (require(tree)) {
  require(ggplot2)
  require(MASS)
  data(cpus, package = "MASS")
  cpus.ltr <- tree(log10(perf) ~ syct + mmin + mmax + cach + chmin + chmax, 
                   data = cpus)
  tree_data <- dendro_data(cpus.ltr)
  ggplot(segment(tree_data)) +
    geom_segment(aes(x = x, y = y, xend = xend, yend = yend, size = n),
      colour = "lightblue"
    ) +
    scale_size("n") +
    geom_text(
      data = label(tree_data),
      aes(x = x, y = y, label = label), vjust = -0.5, size = 4
    ) +
    geom_text(
      data = leaf_label(tree_data),
      aes(x = x, y = y, label = label), vjust = 0.5, size = 3
    ) +
    theme_dendro()
}

ggdendro

Create Dendrograms and Tree Diagrams Using 'ggplot2'

v0.1.22

GPL-2 | GPL-3

Authors

Andrie de Vries [aut, cre], Brian D. Ripley [aut] (author of package tree)

Initial release