In the beginning of this chapter, we learned how to plot a dendrogram, and in the next section we learned about heat maps. In this recipe, we will integrate these two in a single plot. The advantage of using a heat map with dendrograms a is that the visualization provides us with more information.

We will observe in this recipe that we are able to view the clustering via dendrograms drawn over rows and columns, and the color plotted using the heat map provides us with the information as to the strength of this relationship.

For this recipe, we will use the USArrests dataset, which was also used in the prior recipe of this chapter. The techniques of visualization learned in this chapter are a part of a branch of statistics known as unsupervised learning. It is not possible to cover all the techniques (K mean clustering, PCA, and hierarchical clustering), and hence to learn more about this field you should read Chapter 10, Unsupervised Learning...