Special Kinds of Trees

There are 3 special kinds of trees:

• Dendrograms

• Decision Trees

• Flowcharts

Dendrograms

These are binary trees (i.e. each node has at most 2 children).

They are usually used to represent the results of a data mining technique called hierarchical clustering (an algorithm that organizes objects into a hierarchical structure based on a certain similarity metric).

The height of the line that connects nodes in a dendrogram represents the distance between the corresponding objects.

This is a versatile technique and can be used whenever a similarity/distance metric is available. They are commonly used in phylogenetic trees, using genetic distance as a metric.

Decision Trees

Every node represents a decision between 2 or more options.

Decision Trees can be built automatically from labeled data.

Flowcharts

Flowcharts can be used to visualize a process or decision flows.