R: Draw Rectangles Around Hierarchical Clusters

rect.hclust {stats}

R Documentation

Draw Rectangles Around Hierarchical Clusters

Description

Draws rectangles around the branches of a dendrogram highlighting the corresponding clusters. First the dendrogram is cut at a certain level, then a rectangle is drawn around selected branches.

Usage

rect.hclust(tree, k = NULL, which = NULL, x = NULL, h = NULL,
            border = 2, cluster = NULL)

Arguments

`tree`	an object of the type produced by `hclust`.
`k, h`	Scalar. Cut the dendrogram such that either exactly `k` clusters are produced or by cutting at height `h`.
`which, x`	A vector selecting the clusters around which a rectangle should be drawn. `which` selects clusters by number (from left to right in the tree), `x` selects clusters containing the respective horizontal coordinates. Default is `which = 1:k`.
`border`	Vector with border colors for the rectangles.
`cluster`	Optional vector with cluster memberships as returned by `cutree(hclust.obj, k = k)`, can be specified for efficiency if already computed.

Value

(Invisibly) returns a list where each element contains a vector of data points contained in the respective cluster.

Examples

require(graphics)

hca <- hclust(dist(USArrests))
plot(hca)
rect.hclust(hca, k = 3, border = "red")
x <- rect.hclust(hca, h = 50, which = c(2,7), border = 3:4)
x