extract cluster information from the generated dendrogram

Question

In the generated dendrogram graph, the column marks the distance cutoff. Is there a way to get the cluster information for each of these distance cutoffs. In specific, how to do that in Matlab or in R?

Answer 1

If X is your dataset, then in MATLAB the command

Z = linkage(X);

(requires Statistics Toolbox) will carry out hierarchical cluster analysis for you. Z is an (m-1)-by-3 matrix, where m is the number of rows of X. The first and second columns of Z give you the indices of the data points or cluster centroids that have been merged together at each node of the dendrogram, and the third column gives you the distance cutoff at that node.

Is that what you are asking for?