Once upon a time, I made my graphs using Excel because it was the only software that I was aware of for making graphs. Now one can do amazing things with Excel and produce fairly good looking graphs, but after looking at some examples of R graphs, I wanted to learn a bit more about R data visualisation. This post mentions some new plotting functions I recently discovered and have found useful.
This lecture on R data visualisation provides a very nice introduction to producing plots in R, which I highly recommend, so check it out. One really cool trick I learned from the course was the use of identify(), which let's you identify points in a scatter plot. Imagine you were comparing the expression of genes from two different libraries and you wanted to know which gene a particular dot represented. Here's how: