Fitting the grid to the data

gnuplot, by default, arranges our graph with a set of ticmarks at equally spaced intervals, with gridlines to match (if we turn the grid on). If we want to make it easy to read off the values of a particular set of points, we can do better:

How to do it…

The following script will create the previous figure:

set term pngcairo dashed
set out 'xsquared.png'
set samples 6
set key top left
set for [n = 1 : 4] arrow from first n, 0 to first n, n**2 back \ nohead lt 7
set for [n = 1 : 4] arrow from first 0, n**2 to first n, n**2 back \ nohead lt 7
set for [n = 0 : 5] ytics (n**2)
plot [0:5] x**2 with linespoints pt 7 ps 3

How it works…

We have included explicit set terminal and set out commands because we want our linetype specifications to select a dashed line; if you prefer to use colored lines where the figure has a dashed line, you can omit the dashed keyword.

We set a small number of samples because we want to illustrate the technique with a handful of points, that typically...