This happens because PGFPlots only uses one "stack" per axis: You're stacking the second confidence interval on top of the first. The easiest way to fix this is probably to use the approach described in "Is there an easy way of using line thickness as error indicator in a plot?": After plotting the first confidence interval, stack the upper bound on top again, using stack dir=minus
. That way, the stack will be reset to zero, and you can draw the second confidence interval in the same fashion as the first:

\documentclass{standalone}
\usepackage{pgfplots, tikz}
\usepackage{pgfplotstable}
\pgfplotstableread{
temps y_h y_h__inf y_h__sup y_f y_f__inf y_f__sup
1 0.237340 0.135170 0.339511 0.237653 0.135482 0.339823
2 0.561320 0.422007 0.700633 0.165871 0.026558 0.305184
3 0.694760 0.534205 0.855314 0.074856 -0.085698 0.235411
4 0.728306 0.560179 0.896432 0.003361 -0.164765 0.171487
5 0.711710 0.544944 0.878477 -0.044582 -0.211349 0.122184
6 0.671241 0.511191 0.831291 -0.073347 -0.233397 0.086703
7 0.621177 0.471219 0.771135 -0.088418 -0.238376 0.061540
8 0.569354 0.431826 0.706882 -0.094382 -0.231910 0.043146
9 0.519973 0.396571 0.643376 -0.094619 -0.218022 0.028783
10 0.475121 0.366990 0.583251 -0.091467 -0.199598 0.016664
}{\table}
\begin{document}
\begin{tikzpicture}
\begin{axis}
% y_h confidence interval
\addplot [stack plots=y, fill=none, draw=none, forget plot] table [x=temps, y=y_h__inf] {\table} \closedcycle;
\addplot [stack plots=y, fill=gray!50, opacity=0.4, draw opacity=0, area legend] table [x=temps, y expr=\thisrow{y_h__sup}-\thisrow{y_h__inf}] {\table} \closedcycle;
% subtract the upper bound so our stack is back at zero
\addplot [stack plots=y, stack dir=minus, forget plot, draw=none] table [x=temps, y=y_h__sup] {\table};
% y_f confidence interval
\addplot [stack plots=y, fill=none, draw=none, forget plot] table [x=temps, y=y_f__inf] {\table} \closedcycle;
\addplot [stack plots=y, fill=gray!50, opacity=0.4, draw opacity=0, area legend] table [x=temps, y expr=\thisrow{y_f__sup}-\thisrow{y_f__inf}] {\table} \closedcycle;
% the line plots (y_h and y_f)
\addplot [stack plots=false, very thick,smooth,blue] table [x=temps, y=y_h] {\table};
\addplot [stack plots=false, very thick,smooth,blue] table [x=temps, y=y_f] {\table};
\end{axis}
\end{tikzpicture}
\end{document}
It does not work in your MWE because you are overwriting it by also giving the option nodes near coors
to the \addplot
command. Remove the latter one (or specify format here), and it will print. I added a thinspace before the percentage sign, although it can also be recommended to load the siunitx
package and let that format and typeset the values for you.
Anyway, here's the quickfixed version:
\documentclass[border=3pt]{standalone}
\usepackage{pgfplots}
\pgfplotsset{%
width=5cm,
height=18cm,
compat=1.13,
colormap={blackwhite}{gray(0cm)=(1); gray(1cm)=(0.5)},
xticklabels={LPIBG, ALL, HPIBG},
xtick={0,...,2},
ytick=\empty
}
\begin{document}
\begin{tikzpicture}
\begin{axis}[%
enlargelimits=false,
xlabel style={font=\footnotesize},
ylabel style={font=\footnotesize},
legend style={font=\footnotesize},
xticklabel style={font=\footnotesize},
yticklabel style={font=\footnotesize},
colorbar,
colorbar style={%
ytick={0,20,40,60,80,100},
yticklabels={0,20,40,60,80,100},
yticklabel={\pgfmathprintnumber\tick\,\%},
yticklabel style={font=\footnotesize}
},
point meta min=0,
point meta max=100,
nodes near coords={\pgfmathprintnumber\pgfplotspointmeta\,\%},
every node near coord/.append style={xshift=0pt,yshift=-7pt, black, font=\footnotesize},
]
\addplot[
matrix plot,
mesh/cols=3,
point meta=explicit]
table[meta=C]{
x y C
0 0 80
1 0 36
2 0 40
0 1 64
1 1 80
2 1 60
0 2 52
1 2 84
2 2 72
0 3 72
1 3 28
2 3 32
0 4 56
1 4 84
2 4 80
0 5 72
1 5 52
2 5 44
0 6 4
1 6 84
2 6 41
0 7 37
1 7 69
2 7 84
0 8 63
1 8 53
2 8 82
0 9 78
1 9 74
2 9 39
0 10 39
1 10 63
2 10 88
0 11 76
1 11 74
2 11 49
0 12 39
1 12 6
2 12 88
0 13 46
1 13 33
2 13 75
0 14 88
1 14 67
2 14 54
0 15 79
1 15 83
2 15 75
0 16 50
1 16 46
2 16 71
0 17 92
1 17 71
2 17 75
0 18 46
1 18 33
2 18 8
};
\end{axis}
\end{tikzpicture}
\end{document}

Best Answer
You can replace
hide axis
in your code withaxis lines=left, xtick=\empty, ytick=\empty
.