Heatmaps are an incredibly useful tool and ingeneous way of visualising and displaying data and relationships between columns and rows, whatever they may be. Basically, “a heat map is is a graphical representation of data where the individual values contained in a matrix are represented as colors”.
I first came across “heatmaps” in my studies in Molecular Biology at the University of Cape Town where they are very common to show gene expression of microarray data under various conditions and help identify clusters and patterns. For example, see the image below with the typical red and green colour scale used.
