R: Plots of a Divisive Hierarchical Clustering

plot.diana {cluster} | R Documentation

## Plots of a Divisive Hierarchical Clustering

### Description

Creates plots for visualizing a `diana` object.

### Usage

    ## S3 method for class 'diana'
    plot(x, ask = FALSE, which.plots = NULL, main = NULL,
               sub = paste("Divisive Coefficient = ", round(x$dc, digits = 2)),
               adj = 0, nmax.lab = 35, max.strlen = 5, xax.pretty = TRUE, ...)

### Arguments

`x` | an object of class `"diana"`, typically created by `diana(.)`.
`ask` | logical; if true and `which.plots` is `NULL`, `plot.diana` operates in interactive mode, via `menu`.
`which.plots` | integer vector or NULL (default), the latter producing both plots. Otherwise, `which.plots` must contain integers of `1` for a banner plot or `2` for a dendrogram or “clustering tree”.
`main, sub` | main and sub title for the plot, each with a convenient default. See documentation for these arguments in `plot.default`.
`adj` | for label adjustment in `bannerplot()`.
`nmax.lab` | integer indicating the number of labels which is considered too large for single-name labelling the banner plot.
`max.strlen` | positive integer giving the length to which strings are truncated in banner plot labeling.
`xax.pretty` | logical or integer indicating if `pretty(*, n = xax.pretty)` should be used for the x axis. `xax.pretty = FALSE` is for back compatibility.
`...` | graphical parameters (see `par`) may also be supplied and are passed to `bannerplot()` or `pltree()`, respectively.

### Details

When `ask = TRUE`, rather than producing each plot sequentially, `plot.diana` displays a menu listing all the plots that can be produced. If the menu is not desired but a pause between plots is still wanted one must set `par(ask= TRUE)` before invoking the plot command.

The banner displays the hierarchy of clusters, and is equivalent to a tree. See Rousseeuw (1986) or chapter 6 of Kaufman and Rousseeuw (1990). The banner plots the diameter of each cluster being splitted. The observations are listed in the order found by the `diana` algorithm, and the numbers in the `height` vector are represented as bars between the observations.

The leaves of the clustering tree are the original observations. A branch splits up at the diameter of the cluster being splitted.

### Side Effects

An appropriate plot is produced on the current graphics device. This can be one or both of the following choices:
Banner
Clustering tree

### Note

In the banner plot, observation labels are only printed when the number of observations is limited less than `nmax.lab` (35, by default), for readability. Moreover, observation labels are truncated to maximally `max.strlen` (5) characters.

### References

see those in `plot.agnes`.

### See Also

`diana`, `diana.object`, `twins.object`, `par`.

### Examples

    example(diana)# -> dv <- diana(....)

    plot(dv, which = 1, nmax.lab = 100)

    ## wider labels :
    op <- par(mar = par("mar") + c(0, 2, 0,0))
    plot(dv, which = 1, nmax.lab = 100, max.strlen = 12)
    par(op)

[Package cluster version 2.1.0 Index]