dendro_data.tree function

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().

## 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

Returns

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

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()
}

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(s)

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