plot.diana: Plots of a Divisive Hierarchical Clustering

Description

Creates plots for visualizing a diana object.

Usage

plot.diana(x, ask = FALSE, which.plots = NULL,
         main = paste("Banner of ", deparse(attr(x, "Call"))),
         sub  = paste("Divisive Coefficient = ", round(x$dc, digits = 2)),
         adj = 0, nmax.lab = 35, max.strlen = 5, ...)

Arguments

an object of class "diana", created by the function diana.

ask

if TRUE, plot.diana operates in interactive mode.

...

Graphical parameters (see par) may also be supplied as arguments to this function.

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

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.

References

Kaufman, L. and Rousseeuw, P.J. (1990). Finding Groups in Data: An Introduction to Cluster Analysis. Wiley, New York.

Rousseeuw, P.J. (1986). A visual display for hierarchical classification, in Data Analysis and Informatics 4. Edited by E. Diday, Y. Escoufier, L. Lebart, J. Pages, Y. Schektman, and R. Tomassone. North-Holland, Amsterdam. pp. 743-748.

Struyf, A., Hubert, M. and Rousseeuw, P.J. (1997). Integrating Robust Clustering Techniques in S-PLUS, Computational Statistics and Data Analysis, 26, 17-37.