When ask= TRUE
, rather than producing each plot sequentially,
plot.partition
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,
call par(ask= TRUE)
before invoking the plot command.
The clusplot of a cluster partition consists of a two-dimensional
representation of the observations, in which the clusters are
indicated by ellipses (see clusplot.partition
for more
details).
The silhouette plot of a nonhierarchical clustering is fully
described in Rousseeuw (1987) and in chapter 2 of Kaufman and
Rousseeuw (1990).
For each observation i, a bar is drawn, representing its silhouette
width s(i), see silhouette
for details.
Observations are grouped per cluster, starting with cluster 1 at the
top. Observations with a large s(i) (almost 1) are very well
clustered, a small s(i) (around 0) means that the observation lies
between two clusters, and observations with a negative s(i) are
probably placed in the wrong cluster.
A clustering can be performed for several values of k
(the number of
clusters). Finally, choose the value of k
with the largest overall
average silhouette width.