Tutorial: Make Latex ready plots using gnuplot.

Gnuplot is a free yet easy to use command line plotter for the Linux OS. You can also install it on Mac OS X and Windows. If you are using Mac OS X and want the OS X feel in your plots you can type
>set terminal aqua

With gnuplot you can either plot data files or functions, in this case we will plot (sin(x)/x)^2, first we want to plot it and make sure we get the right plot.

1) open gnuplot and type
>plot (sin(x)/x)**2

2) Make a new file i.e. plot.txt and open it in any text editor, add the lines

set terminal epslatex
set output "myplot.eps"

This two lines will tell gnuplot that the output file has to be an encapsulated postscript (eps) with name myplot.eps, now you can add to the file the plot you want to make.

set key off
set xlabel '$x$'
set ylabel '$(\frac{sin(x)}{x})^{2}$'
plot (sin(x)/x)**2

First set the options of your plot, xlabel, ylabel, etc, and then input the plot command. Note that you can input data in the latex commands and latex will translate that to actual formatted text equations. Now you can save the file.

3) In the terminal type the command
>gnuplot plot.txt

You will notice two new files in your directory. myplot.eps and myplot.tex

4) If you already have a tex document you insert your new plot on it. First make sure you have the following two lines in the headers of your tex file;

\usepackage{graphicx}
\usepackage{epstopdf}

gnuplot warns you about adding the first one but not the second one in the help pages.

now just place your graphic with the command, \input{myplot}

5) Or you could also compile myplot.tex file directly only a few modifications are needed, first open myplot.tex and add the following lines

\documentclass[14pt]{article}
\usepackage{graphicx}
\usepackage{epstopdf}
\begin{document}

skip the rest of the text and locate the last line
\endinput
and delete it. Finally add the line

\end{document}

And that is it, now you just need to compile your tex document to make it a pdf. Sometimes pdflatex have problems making the plot when both files have the same name myplot.tex & myplot.eps, in such a case, change the name of the eps file. i.e. othername.eps and change the line in myplot.tex
\includegraphics{myplot}
to
\includegraphics{./othername.eps}



Cheers.