# How to minimize the ink-to-data ratio for pgfplots

Tufte advocates to "minimize the ink-to-data ratio" for charts. I am trying to style a multi data series bar chart, that can have a grid and axes as shown below (chart at the left is from the Economist and on the right my attempt).

Here is the code:

\documentclass[justified]{tufte-book}
\usepackage{pgfplots,lipsum}
\begin{document}
\section{Bar Charts}

\lipsum[1-2]\vfill

\begin{figure*}[htbp]

\fbox{
\begin{tikzpicture}
\centering
\begin{axis}[
ybar,
title={Cumulative Progress of Works},
height=8cm,
width=15.5cm,
bar width=0.4cm,
ymajorgrids, tick align=inside,
enlarge  y limits={value=.2,auto}, % see the upper
ymin=0,
ymax=100,
axis x line=bottom,
axis y line=right,
%enlarge x limits =e,
legend style={at={(0.5,-0.2)},
anchor=north,legend columns=-1},
ylabel={Percentage (\%)},
symbolic x coords={
Sep-11,Oct-11,Nov-11,Dec-11,
Jan-12,Feb-12,
Mar-12,
Apr-12},
xtick=data,
nodes near coords,
every node near coord/.append style={
anchor=mid west,
rotate=70
}
]
(Sep-11,75.4064)
(Oct-11, 72.7961)
(Nov-11,94.4597)
(Dec-11,66.6786)
(Jan-12,67.5600)
(Feb-12,88.2339)
(Mar-12,78.6138)
(Apr-12,58.9129) };
(Sep-11,75.4064)
(Oct-11, 89.7961)
(Nov-11,94.4597)
(Dec-11,76.6786)
(Jan-12,77.5600)
(Feb-12,78.2339)
(Mar-12,88.6138)
(Apr-12,78.9129) };
(Sep-11,75.4064)
(Oct-11, 89.7961)
(Nov-11,94.4597)
(Dec-11,76.6786)
(Jan-12,77.5600)
(Feb-12,78.2339)
(Mar-12,88.6138)
(Apr-12,78.9129) };

\legend{First Fix,Second Fix,Third Fix}
\end{axis}
\end{tikzpicture}
}

\caption{\protect\raggedright Cumulative progress for all MEP works. Notice the slower rate of production during the last three months.}
\end{figure*}

\lipsum[1-3]
\end{document}


I have moved the y-axis to the right, but cannot get rid of the axis line. The plot is also not fitting within the plot width, despite using \enlarge.

Edit

And thanks to Jake the ugly duckling has been transformed to the following, with minor variations to the code as suggested by Jake. I have only added a stronger color for one of the bars in order to highlight it:

-
Related question: How can I draw a chart in the economist style with pgfplots? –  Jake Oct 14 '11 at 6:10
@Jake Thanks didn't see the question. Will have a look. –  Yiannis Lazarides Oct 14 '11 at 6:23
Do I understand you correctly that the economist plot is an example where the ink-to-data ratio is minimized according to Tufte's criteria? –  maxschlepzig Oct 14 '11 at 7:27
@maxschlepzig They are considered to be; for example in the chart above, there is no vertical grid and by positioning the axis at the right, you highlight the latest data. Compare this with the typical scientific graph in a box, with tick marks on all sides. Some examples at economist.com/blogs/dailychart?page=8 –  Yiannis Lazarides Oct 14 '11 at 7:33

To hide the y axis line, you'll have to use y axis line style={opacity=0}, to hide the tick marks, set tickwidth=0pt.

I assume you also don't want an arrow tip for the x-axis, so you should set x axis line*=bottom (the * disables the arrow tip).

Furthermore, I would round the percentages to integers, since the two decimal places don't really convey much information in this case. You can do that by setting nodes near coords={ \pgfmathprintnumber[precision=0]{\pgfplotspointmeta} }. By removing the decimals, the numbers become short enough to print them horizontally, which looks much neater.

To make the whole chart look more "Tuftian", you can overlay the horizontal grid lines in white over the columns axis on top, major grid style={draw=white}. The nodes near coords will still be above the grid.

To make the chart fit into the plot area, you can set  enlarge y limits={value=.1,upper}. You don't have to set enlarge x limits, the axis wide ybar style takes care of that.

To add some extra space between the legend entries, you can add /tikz/every even column/.append style={column sep=0.5cm} to your legend style (see How can I adjust the horizontal spacing between legend entries in PGFPlots?).

Here's the result of my suggestions:

And here's the code:

 \documentclass[justified]{article}
\usepackage{pgfplots,lipsum}
\begin{document}
\section{Bar Charts}

\begin{figure*}[htbp]

\fbox{
\begin{tikzpicture}
\centering
\begin{axis}[
ybar, axis on top,
title={Cumulative Progress of Works},
height=8cm, width=15.5cm,
bar width=0.4cm,
ymajorgrids, tick align=inside,
major grid style={draw=white},
enlarge y limits={value=.1,upper},
ymin=0, ymax=100,
axis x line*=bottom,
axis y line*=right,
y axis line style={opacity=0},
tickwidth=0pt,
enlarge x limits=true,
legend style={
at={(0.5,-0.2)},
anchor=north,
legend columns=-1,
/tikz/every even column/.append style={column sep=0.5cm}
},
ylabel={Percentage (\%)},
symbolic x coords={
Sep-11,Oct-11,Nov-11,Dec-11,
Jan-12,Feb-12,
Mar-12,
Apr-12},
xtick=data,
nodes near coords={
\pgfmathprintnumber[precision=0]{\pgfplotspointmeta}
}
]
(Sep-11,75.4064)
(Oct-11, 72.7961)
(Nov-11,94.4597)
(Dec-11,66.6786)
(Jan-12,67.5600)
(Feb-12,88.2339)
(Mar-12,78.6138)
(Apr-12,58.9129) };
(Sep-11,75.4064)
(Oct-11, 89.7961)
(Nov-11,94.4597)
(Dec-11,76.6786)
(Jan-12,77.5600)
(Feb-12,78.2339)
(Mar-12,88.6138)
(Apr-12,78.9129) };
(Sep-11,75.4064)
(Oct-11, 89.7961)
(Nov-11,94.4597)
(Dec-11,76.6786)
(Jan-12,77.5600)
(Feb-12,78.2339)
(Mar-12,88.6138)
(Apr-12,78.9129) };

\legend{First Fix,Second Fix,Third Fix}
\end{axis}
\end{tikzpicture}
}

\caption{\protect\raggedright Cumulative progress for all MEP works. Notice the slower rate of production during the last three months.}
\end{figure*}

\end{document}

-
Thanks, much better looking than the Economist and thanks for fixing the code on a almost duplicate question. Is there a way to space out the legend a bit? –  Yiannis Lazarides Oct 14 '11 at 6:51
You can add /tikz/every even column/.append style={column sep=0.5cm} to your legend style. See How can I adjust the horizontal spacing between legend entries in PGFPlots? –  Jake Oct 14 '11 at 6:59
Thanks again, this did it. –  Yiannis Lazarides Oct 14 '11 at 7:08

Slightly less ink:

\documentclass[justified]{tufte-book}
\usepackage{pgfplots,lipsum}
\begin{document}

\begin{figure*}[htbp]
\begin{tikzpicture}
\centering
\begin{axis}[
ybar, axis on top,
title={Cumulative Progress of Works},
height=8cm, width=15.5cm,
bar width=0.4cm,
ymajorgrids, tick align=inside,
major grid style={draw=white},
enlarge y limits={value=.1,upper},
ymin=0, ymax=100,
axis x line*=bottom,
axis y line*=right,
y axis line style={opacity=0},
x axis line style={opacity=0},
tickwidth=0pt,
legend style={draw=none},
enlarge x limits=true,
legend style={
at={(0.5,-0.1)},
anchor=north,
legend columns=-1,
/tikz/every even column/.append style={column sep=0.5cm}
},
ylabel={Percentage (\%)},
symbolic x coords={
Sep-11,Oct-11,Nov-11,Dec-11,
Jan-12,Feb-12,
Mar-12,
Apr-12},
xtick=data,
nodes near coords={
\pgfmathprintnumber[precision=0]{\pgfplotspointmeta}
}
]
(Sep-11,75.4064)
(Oct-11, 72.7961)
(Nov-11,94.4597)
(Dec-11,66.6786)
(Jan-12,67.5600)
(Feb-12,88.2339)
(Mar-12,78.6138)
(Apr-12,58.9129) };
(Sep-11,75.4064)
(Oct-11, 89.7961)
(Nov-11,94.4597)
(Dec-11,76.6786)
(Jan-12,77.5600)
(Feb-12,78.2339)
(Mar-12,88.6138)
(Apr-12,78.9129) };
(Sep-11,75.4064)
(Oct-11, 89.7961)
(Nov-11,94.4597)
(Dec-11,76.6786)
(Jan-12,77.5600)
(Feb-12,78.2339)
(Mar-12,88.6138)
(Apr-12,78.9129) };

\legend{First Fix,Second Fix,Third Fix}
\end{axis}
\end{tikzpicture}
\caption{\protect\raggedright Cumulative progress for all MEP works. Notice the slower rate of production during the last three months.}
\end{figure*}

\end{document

-
If I see this correctly, the difference between the this and the other answer is that the x axis line is hidden by adding the line x axis line style={opacity=0} below the line y axis line style={opacity=0}, right? –  Jake Jan 14 '13 at 13:54
Yes, and it gets rid of the box around the labels and the box around the whole plot. Bringing the labels a little closer makes it clearer that they belong to the plot without needing any boxes. –  Benjamin McKay Jan 14 '13 at 14:10
Ah yes, I see. Nice improvements! Generally, it's probably a good idea to provide some explanation in an answer instead of only posting code. –  Jake Jan 14 '13 at 14:23
Nice improvements, thanks. –  Yiannis Lazarides Jan 14 '13 at 16:22