- What is a Dendrogram?
A Dendrogram demonstrates the hierarchical relationship between objects.
![](/2018/content/images/2018/08/Screen-Shot-2018-08-29-at-8.37.19-PM.png)
We can think of Dendrograms as a way to represents nested clusters.
![](/2018/content/images/2018/08/Screen-Shot-2018-08-29-at-8.43.31-PM.png)
2. How to read a Dendrogram?
The key is to focus on the height at which any two objects are joined together.
Look at the image above, we see:
- E and F are the closest to each other.
- The cluster of A and B and the cluster of C,D,E and F are the furthest from each other.
![](/2018/content/images/2018/08/Screen-Shot-2018-08-29-at-8.42.15-PM.png)
3. Applications
![](/2018/content/images/2018/08/Screen-Shot-2018-08-29-at-8.55.02-PM.png)
An Animal Classes Dendrogram
![](/2018/content/images/2018/08/Screen-Shot-2018-08-29-at-9.02.57-PM.png)
A Dog Breed Dendrogram
4. Why Dendrogram can be bad?
- It does not accurately show how many clusters there actually are.
If we cut the single linkage tree at the point shown below, we would say that there are two clusters.
![](/2018/content/images/2018/08/Screen-Shot-2018-08-29-at-9.08.29-PM.png)
However, if we cut the tree lower we might say that there is one cluster and two singletons.
![](/2018/content/images/2018/08/Screen-Shot-2018-08-29-at-9.08.33-PM.png)