Plotting measured data with gnuplot
In conjunction with a physics lecture I am attending this semester a fellow student and I had to create a measurement report of an experiment we did. Working on that report I realized that I had never before felt the need for plotting measured data with a computer. Therefore I naturally did not know what freely available tool could help me with that task. Another fellow student then pointet out gnuplot to me and I gave it a try. And what can I say. I was able to create the desired plot very fast and it was pretty too.
About gnuplot:
“Gnuplot is a portable command-line driven interactive data and function plotting utility for UNIX, IBM OS/2, MS Windows, DOS, Macintosh, VMS, Atari and many other platforms.”
One of our final results looked like this:
This illustrates of course only the very basic features of the tool. It’s much more powerfull than our example shows.
Some usefull commands I used to customize the plot:
As I wanted a double logarithmic scale I typed
set logscale xy
I also wanted to see the scale in my plot so I typed
set grid xtics mxtics ytics mytics
I set the lables of the axes with
set xlabel “x name” and set ylabel “y name”
(btw this labeling can also be enhanced with LaTeX style formula expressions)
and I defined the axes’ ranges with
set xrange [1:100] and set yrange [1:100]
the smoothing (interpolation) of the curve can be accomplished by specifying
smooth csplines or smooth bezier
within the plot command.