R: Data Analysis and Visualization

Summarizing multivariate data in a single heat map

In the preceding couple of recipes, we looked at representing a matrix of data along two axes on a heat map. In this recipe, we will learn how to summarize multivariate data using a heat map.

Getting ready

We are only using the base graphics functions for this recipe. So, just open up the R prompt and type in the following code. We will use the nba.csv example dataset for this recipe. So, let's first load it:

nba <- read.csv("nba.csv")

This example dataset, which shows some statistics on the top scorers in NBA basketball games has been taken from a blog post on FlowingData (see http://flowingdata.com/2010/01/21/how-to-make-a-heatmap-a-quick-and-easy-solution/ for details). The original data is from ...