Graphics Reference
In-Depth Information
Figure
.
.
PCA unit display: absolute visualization of contributions through point size and color
(green and blue refer, respectively, to the first and second factors)
A useful interactive capability in this sense is based on the dendrogram dynamic
cutting:changingthecutlevelofthedendrogram,theusercanconsequentlyvisualize
the resulting partition on the factorial plane. Obtained clusters can be described in
terms of descriptive tables and charts; the user can decide to drop a cluster from the
analysis or to aggregate two or more homogeneous clusters. As a consequence of the
user action, the analysis restarts again and the results change.
Aside from the classical dendrogram, alternative views can be obtained using the
tree views that aretypical of modernoperating systemuserinterfaces. An illustrative
example is shown in Fig.
.
. It is an innovative representation useful for visualizing
results of a cluster analysis that also allows the user to query a particular level of the
tree.
he user can collapse (expand) a particular cluster in order to hide (to show) the
items included in that cluster.Drill-down functionalities allow one tobrowse agiven
cluster, while linking functionalities between the tree-view representation and the
factorial plane provide the user the capability to select a different cut level in order
to visualize the corresponding clusters on the factorial plane.
