Plot example in 06

[bkmgit]

The plotting example in 06 could be improved to be more realistic. For example by using graph from plotutils if it is available in all environments.

[arendsee]

@bkmgit Did you have something like this in mind:

We can generate plots on the command line with the plotutils package. You can install this package with:

$ sudo apt-get install plotutils

Returning the gyre dataset, say we want to compare each the A and B files from each dataset. We can join two of the columns with the paste command:

$ paste NENE01751[AB].txt | graph -T png -m 0 -S 3 -X "A values" -Y "B values" -L "NENE01751 A vs B" > NENE01751.png

The -T option sets the output format. We choose png. The default format is "meta", which, as the documentation graph --help helpfully tells us, is probably not what we want.

The -m 0 option sets the format of the lines between points. We want a scatterplot. we set this to zero indicating no lines between points. You can experiment with other values (1,2, ...).

The -S option sets the shape of the points in the plot. We chose 3, which represents data points with X's.

The -X, -Y and -L options set the x-label, y-label, and main plot title, respectively.

We can wrap this in a shell script:

for file in *A.txt
do
    name=${file//A.txt}
    paste ${name}A.txt ${name}B.txt | graph -T png -m 0 -S 3 -X "A values" -Y "B values" -L "$name A vs B" > $name.png
done

The ${file//A.txt} command is a Bash shortcut to remove the exact string "A.txt" from the end of a variable. In this case, it lets us convert from "NENE01751A.txt" to "NENE01751".