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Producing Graphs for Publication

This page describes several ways to produce publication quality graphics for LaTeX via real examples.

LaTeX UsingTex

This section describes a technique following the UsingTex guidelines.

Here is the outline of the LaTeX file used to include the figure (example for REVTeX4 for publication is APS physics journals with a two column format.)

\documentclass[prl,10pt,twocolumn]{revtex4}
\usepackage{graphicx}    % Used to import the graphics

\begin{document}
%...
\begin{figure}[t]
\begin{center}
\showthe\columnwidth % Use this to determine the width of the figure.
\includegraphics[width=\columnwidth]{fig1.eps}
\caption{\label{fig:sin_cos} Plot of the sine and cosine functions.}
\end{center}
\end{figure}
%...
\end{document}

Determining the Figure Size

The first step is to determine the size of the figure: this way, when the graphic is included, it will not be resized, and the fonts etc. will be exactly as you set them rather than scaled (and possibly distored). This can be done in LaTeX by explicitly setting the width of the figure and using the \showthe command to print this width. (In the example above, the figure width is set to the \columnwidth.)

When the file is processed by LaTeX, look at the output. The example above produces the following output (Note: LaTeX will pause after the \showthe command, press enter to continue):

This is TeX, Version 3.14159 (Web2C 7.4.5)
LaTeX2e <2001/06/01>
...
> 246.0pt.
l.8     \showthe\columnwidth
% Use this to determine the width of the figure.
?
<fig1.eps> [1] (./tst.aux) )
...

Thus, the figure will be 246.0pt wide. There are 1 inch = 72pt, so this means that the figure width should be 3.416666 inches. The heigth depends on the content of the figure, but the golden mean may be used to make a pleasing figure. Once this is determined, the figure.figsize property can be used to set the default figure size.

fig_width_pt = 246.0  # Get this from LaTeX using \showthe\columnwidth

inches_per_pt = 1.0/72.0                # Convert pt to inches
golden_mean = (sqrt(5)-1.0)/2.0         # Aesthetic ratio
fig_width = fig_width_pt*inched_per_pt  # width in inches
fig_height =fig_width*golden_mean       # height in inches
fig_size = [fig_width,fig_height]

Setting Font Sizes

Since the figure will not be scaled down, we may explicitly set the font sizes.

          'font.size' : 10,
'axes.labelsize' : 10,
'font.size' : 10,
'text.fontsize' : 10,
'xtick.labelsize' : 8,
'ytick.labelsize' : 8,

Fine Tuning

With these smaller plot sizes, the default margins are not enough to display the axis labels, so we need to specify large margins. We do this with an explicit call to the axes() function. In this example, we only have one axis. The typeset LaTeX document will have whitespace on either side of the figure, so we do not need to include this in the figure. Thus, we keep just a bit of whitespace at the top and to the right so that the labels do not extend beyond the bounding box, and add more space to the bottom for the x label:

pylab.axes([0.125,0.2,0.95-0.125,0.95-0.2])

Putting it all Together

Here is the python file that generates the plots.

   1 import pylab
2 from pylab import arange,pi,sin,cos,sqrt
3
4 fig_width_pt = 246.0  # Get this from LaTeX using \showthe\columnwidth
5
6 inches_per_pt = 1.0/72.0                # Convert pt to inch
7 golden_mean = (sqrt(5)-1.0)/2.0         # Aesthetic ratio
8 fig_width = fig_width_pt*inches_per_pt  # width in inches
9 fig_height = fig_width*golden_mean      # height in inches
10 fig_size =  [fig_width,fig_height]
11
12 params = {'backend': 'ps',
13           'axes.labelsize': 10,
14           'text.fontsize': 10,
15           'xtick.labelsize': 8,
16           'ytick.labelsize': 8,
17           'text.usetex': True,
18           'figure.figsize': fig_size}
19
20 pylab.rcParams.update(params)
21
22 # Generate data
23 x = pylab.arange(-2*pi,2*pi,0.01)
24 y1 = sin(x)
25 y2 = cos(x)
26
27 # Plot data
28 pylab.figure(1)
29 pylab.clf()
30 pylab.axes([0.125,0.2,0.95-0.125,0.95-0.2])
31 pylab.plot(x,y1,'g:',label='$\sin(x)$')
32 pylab.plot(x,y2,'-b',label='$\cos(x)$')
33 pylab.xlabel('$x$ (radians)')
34 pylab.ylabel('$y$')
35 pylab.legend()
36 pylab.savefig('fig1.eps')


LaTeX using psfrag

To ensure that your graphics use exactly the same fonts as your document, you can have LaTeX generate and substitute the text for your graph using the psfrag package. This is a good option if you have problems with the text.usetex method (for example, if the appropriate fonts cannot be found.)

To do this, simply use plain text for the labels and then replace them using the psfrag package. Here are the modified files to make use of this method:

\documentclass[prl,10pt,twocolumn]{revtex4}
\usepackage{graphicx}    % Used to import the graphics
\usepackage{psfrag}

\begin{document}
%...
\begin{figure}[t]
\begin{center}
{\footnotesize                  % Replace tick-lables with smaller font.
\psfrag{1.0}{\hphantom{+}1.0} % Insert space for alignment with
\psfrag{0.5}{\hphantom{+}0.5} % negative numbers.
\psfrag{0.0}{\hphantom{+}0.0}
\psfrag{-0.5}{-0.5}
\psfrag{-1.0}{-1.0}
\psfrag{-8}{-8}
\psfrag{-6}{-6}
\psfrag{-4}{-4}
\psfrag{-2}{-2}
\psfrag{0}{\hphantom{+}0}
\psfrag{2}{\hphantom{+}2}
\psfrag{4}{\hphantom{+}4}
\psfrag{6}{\hphantom{+}6}
\psfrag{8}{\hphantom{+}8}
}
\psfrag{sin(x)}{$\sin(x)$}
\psfrag{cos(x)}{$\cos(x)$}
\psfrag{x (radians)}{$x$ (radians)}
\psfrag{y}{$y$}
\showthe\columnwidth % Use this to determine the width of the figure.
\includegraphics[width=\columnwidth]{fig2.eps}\\
\includegraphics{fig2.eps}
\caption{\label{fig:sin_cos} Plot of the sine and cosine functions.}
\end{center}
\end{figure}
%...
\end{document}

   1 import pylab
2 from pylab import arange,pi,sin,cos,sqrt
3
4 fig_width_pt = 246.0  # Get this from LaTeX using \showthe\columnwidth
5
6 inches_per_pt = 1.0/72.0                # Convert pt to inch
7 golden_mean = (sqrt(5)-1.0)/2.0         # Aesthetic ratio
8 fig_width = fig_width_pt*inches_per_pt  # width in inches
9 fig_height = fig_width*golden_mean      # height in inches
10 fig_size =  [fig_width,fig_height]
11
12 params = {'backend': 'ps',
13           'axes.labelsize': 10,
14           'text.fontsize': 10,
15           'xtick.labelsize': 8,
16           'ytick.labelsize': 8,
17           'text.usetex': False,
18           'figure.figsize': fig_size}
19
20 pylab.rcParams.update(params)
21
22 # Generate data
23 x = pylab.arange(-2*pi,2*pi,0.01)
24 y1 = sin(x)
25 y2 = cos(x)
26
27 # Plot data
28 # Plot data
29 pylab.figure(1)
30 pylab.clf()
31 pylab.axes([0.125,0.2,0.95-0.125,0.95-0.2])
32 pylab.plot(x,y1,'g:',label='sin(x)')
33 pylab.plot(x,y2,'-b',label='cos(x)')