Extract data from regression tree object for plotting using ggplot.

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

See also

ggdendrogram()

Other dendro_data methods: dendro_data(), dendro_data.rpart(), dendrogram_data(), rpart_labels()

Other tree functions: get_data_tree_leaf_labels(), tree_labels(), tree_segments()

Author

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, linewidth = 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()
}
#> Loading required package: tree
#> Loading required package: MASS