Dendrograms can be created by querying a basic webservice which we run for the purpose of some data analysis jobs. The webservice runs R jobs on a mini job-scheduling system. Creating a dendrogram in R is just a few simple steps which are outlined below:
- We create a distance matrix from our similarity matrix using the R dist() command using its default arguments.
- We then run a hierarchical cluster analysis on this distance matrix using the R hclust() method passing it the distance matrix created in the previous step as its only parameter.
- Finally we output the dendrogram by creating a png image and using R’s plot() passing it the output of hclust and a set of labels which are the line names which were passed to R from Flapjack.
The resulting image is passed back to Flapjack for display.