# Problem with error bars while using pgfplots

I'm new to pgfplots, but it seems like a really useful package. However, I can't quite figure out how to use error bars.

Below is the code to my column chart, where some columns should include an error bar. I figured out that I needed to use a different \addplot command for the error bars, but they are still not showing.

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.7}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
width  = 0.85*\textwidth,
height = 8cm,
major x tick style = transparent,
ybar=2*\pgflinewidth,
bar width=14pt,
ymajorgrids = true,
ylabel = {Concentration [mg/L]},
symbolic x coords={1,2,3,4},
xtick = data,
scaled y ticks = false,
enlarge x limits=0.25,
ymin=0,
legend cell align=left,
legend style={
at={(1,-0.40)},
anchor=south east,
column sep=1ex
}
]
coordinates {
(1, 133.1)
(2,251.7)
(3,372.4)
(4,517.9)
};

coordinates {
(1,97.4) +- (0.0, 11.0)
(2,175.5) +- (0.0, 3.86)
(3,290.8) +- (0.0, 3.14)
(4,482.8) +- (0.0, 15.3)
};

coordinates {
(1,116.9)
(2,150.2) +- (0.0, 0.56)
(3,289.0) +- (0.0, 13.2)
(4,429.6) +- (0.0, 29.0)
};

\legend{Untreated solution,Treated with A,Treated with B}
\end{axis}
\end{tikzpicture}
\end{document}


Do anyone know why this doesn't work? Is it something in my \begin{axis} settings that prevents them from showing?

• Also, if anyone has a better idea on how to achieve this, feel free to let me know. I don't necessarily have to use pgfplots, but I just want a grouped column chart with error bars. – Christian P. Jan 8 at 18:07
• Welcome to TeX.SE! I've never seen something like \addplot+[error bars/.cd,,addplot[y dir=both,y explicit]. Are you sure you can nest the addplots lie this? – marmot Jan 8 at 18:09
• Thanks, I must have inserted them wrongly. It works now! – Christian P. Jan 8 at 18:15

If I do not nest addplots, I get

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.7}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
width  = 0.85*\textwidth,
height = 8cm,
major x tick style = transparent,
ybar=2*\pgflinewidth,
bar width=14pt,
ymajorgrids = true,
ylabel = {Concentration [mg/L]},
symbolic x coords={1,2,3,4},
xtick = data,
scaled y ticks = false,
enlarge x limits=0.25,
ymin=0,
legend cell align=left,
legend style={
at={(1,-0.40)},
anchor=south east,
column sep=1ex
}
]
coordinates {
(1, 133.1)
(2,251.7)
(3,372.4)
(4,517.9)
};

coordinates {
(1,97.4) +- (0.0, 11.0)
(2,175.5) +- (0.0, 3.86)
(3,290.8) +- (0.0, 3.14)
(4,482.8) +- (0.0, 15.3)
};

coordinates {
(1,116.9)
(2,150.2) +- (0.0, 0.56)
(3,289.0) +- (0.0, 13.2)
(4,429.6) +- (0.0, 29.0)
};

\legend{Untreated solution,Treated with A,Treated with B}
\end{axis}
\end{tikzpicture}
\end{document}


i.e. error bars appear wherever you have +- in your data.

• Yes! Thanks a lot, this works like a charm. Don't know why I wrote it that way, I guess I wasn't paying enough attention when changing the addplot to addplot+. One further question, though. Is it possible to change the colours of the bars? – Christian P. Jan 8 at 18:17
• @ChristianP. Certainly, see for example tex.stackexchange.com/a/468836 – Torbjørn T. Jan 8 at 18:19
• @ChristianP. Yes. Please see this recent question, which has two answers, one in which the colors are set directly, and another one in which the cycle list gets modified. – marmot Jan 8 at 18:19