Every time I use gnuplot, I am amazed at how difficult it is to conjure up the simplest graphs, so when I finally get to the bottom of one, I’ll try to post the solution here as a reference for myself, and anyone else who might come looking.

If you’re new to gnuplot, you might want to get out now while you still can

The box and whiskers plot

There are a few different styles of box and whiskers plots and this link gives a pretty good description.

The two gotchas for were what values you need and in what order. These scripts are set up to use the following columns, in order:

• X value (for ordering left-right across the graph)
• Min
• 1st Quartile
• Median
• 3rd Quartile
• Max

The other gotcha I had was wanting to have labels across the x-axis rather than numbers. To accomplish this, I added a 7th column with the label, then I used the following:

set xrange[0:3]
set yrange[0:10]

# Data columns: X Min 1stQuartile Median 3rdQuartile Max Titles
set bars 4.0
set style fill empty
plot 'data.csv' using 1:3:2:6:5:xticlabels(7) with candlesticks title 'Quartiles' whiskerbars, \
  ''         using 1:4:4:4:4 with candlesticks lt -1 notitle

The xticlabels(7) is the key to the x-axis labels, saying to use the values from column 7 for the labels.