Although Hadoop MapReduce jobs can generate interesting analytics, making sense of those results and getting a detailed understanding about the data often requires us to see the overall trends in the data. The human eye is remarkably good at detecting patterns, and plotting the data often yields a deeper understanding of the data. Therefore, we often plot the results of Hadoop jobs using a plotting program.
This recipe explains how to use gnuplot, which is a free and powerful plotting program used to plot Hadoop results.
This recipe assumes that you have followed the previous recipe, Calculating frequency distributions and sorting using MapReduce. If you have not done this, follow this recipe. Install the gnuplot plotting program by following the instructions in http://www.gnuplot.info/.