| dendro_data.rpart {ggdendro} | R Documentation |
Extracts data to plot line segments and labels from a rpart classification tree object. This data can then be manipulated or plotted, e.g. using ggplot.
## S3 method for class 'rpart' dendro_data(model, uniform = FALSE, branch = 1, compress = FALSE, nspace, margin = 0, minbranch = 0.3, ...)
model |
object of class "tree", e.g. the output of tree() |
uniform |
if TRUE, uniform vertical spacing of the nodes is used; this may be less cluttered when fitting a large plot onto a page. The default is to use a non-uniform spacing proportional to the error in the fit. |
branch |
controls the shape of the branches from parent to child node. Any number from 0 to 1 is allowed. A value of 1 gives square shouldered branches, a value of 0 give V shaped branches, with other values being intermediate. |
compress |
if FALSE, the leaf nodes will be at the horizontal plot coordinates of 1:nleaves. If TRUE, the routine attempts a more compact arrangement of the tree. The compaction algorithm assumes uniform=TRUE; surprisingly, the result is usually an improvement even when that is not the case. |
nspace |
the amount of extra space between a node with children and a leaf, as compared to the minimal space between leaves. Applies to compressed trees only. The default is the value of branch. |
margin |
an extra fraction of white space to leave around the borders of the tree. (Long labels sometimes get cut off by the default computation). |
minbranch |
set the minimum length for a branch to minbranch times the average branch length. This parameter is ignored if uniform=TRUE. Sometimes a split will give very little improvement, or even (in the classification case) no improvement at all. A tree with branch lengths strictly proportional to improvement leaves no room to squeeze in node labels. |
... |
ignored |
This code is in essence a copy of plot.rpart, retaining the plot data but without plotting toa plot device.
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 |
Other dendro_data methods: dendro_data.dendrogram,
dendro_data.hclust;
dendro_data.tree;
dendrogram_data; rpart_labels
Other rpart functions: rpart_labels;
rpart_segments
require(rpart)
require(ggplot2)
fit <- rpart(Kyphosis ~ Age + Number + Start, method="class", data=kyphosis)
fitr <- dendro_data(fit)
ggplot() +
geom_segment(data=fitr$segments, aes(x=x, y=y, xend=xend, yend=yend)) +
geom_text(data=fitr$labels, aes(x=x, y=y, label=label)) +
geom_text(data=fitr$leaf_labels, aes(x=x, y=y, label=label)) +
theme_dendro()