Labeling chart series with pgfplots

Question

I have a stacked area chart where several areas have just about 1-2 mm height.

What I'm now planning to do is the following:

• remove the legend
• where there is enough space for it add the series label directly in the chart
• where there is not enough space for it add a black line pointing to the origin area in the chart and at the other end of the line print the series label

Is this possible with pgfplots?

My LaTeX code looks like this:

\documentclass{article}
\usepackage{pgfplots}
\usepackage{xcolor}
\usepackage{filecontents}

\pgfplotsset{
compat=newest, 
every x tick label/.append style={rotate=45,anchor=east,yshift=-0.3cm}, 
axis lines*=left,
table/col sep=semicolon,
}

\begin{document}

\definecolor{gray1}{HTML}{828d94}
\definecolor{gray2}{HTML}{9ea6ab}
\definecolor{gray3}{HTML}{b9bfc3}
\definecolor{gray4}{HTML}{d4d8db}
\definecolor{bronze1}{HTML}{bab194}
\definecolor{bronze2}{HTML}{cec7b3}
\definecolor{bronze3}{HTML}{e2ded2}
\definecolor{bronze4}{HTML}{f6f5f1}
\definecolor{green1}{HTML}{94bab1}
\definecolor{green2}{HTML}{b3cec7}
\definecolor{green3}{HTML}{d2e2de}
\definecolor{green4}{HTML}{f1f6f5}

\begin{filecontents}{sample.csv}
Metrik Nr;Small A;Small B;Small C;Small D;Mid A;Mid B;Mid C;Mid D;Big A;Big B;Big C;Big D;Gesamt;Small A Prozent;Small B Prozent;Small C Prozent;Small D Prozent;Mid A Prozent;Mid B Prozent;Mid C Prozent;Mid D Prozent;Big A Prozent;Big B Prozent;Big C Prozent;Big D Prozent
1;20.0;0.5;0.5;2.0;0.5;0.5;0.5;0.5;20.0;5.0;5.0;2.0;57;35.0877193;0.877192982;0.877192982;3.50877193;0.877192982;0.877192982;0.877192982;0.877192982;35.0877193;8.771929825;8.771929825;3.50877193
2;10.0;0.5;0.5;0.5;0.5;0.5;0.5;0.5;12.0;20.0;8.0;0.5;54;18.51851852;0.925925926;0.925925926;0.925925926;0.925925926;0.925925926;0.925925926;0.925925926;22.22222222;37.03703704;14.81481481;0.925925926
3;7.00;2.00;2.00;2.00;1.00;1.00;1.00;1.00;20.00;10.00;10.00;2.00;59;11.86440678;3.389830508;3.389830508;3.389830508;1.694915254;1.694915254;1.694915254;1.694915254;33.89830508;16.94915254;16.94915254;3.389830508
\end{filecontents}



\begin{tikzpicture}[]
\begin{axis}[
    height=0.85\textheight,
    width=\textwidth,
    xtick={1,2,3},
    xticklabels={Metric 1, Metric 2, Metric 3},
    yticklabel={\pgfmathparse{\tick}\pgfmathprintnumber{\pgfmathresult}\%},    
    ymin=0,
    ymax=100,
    stack plots=y,
    area style,
    scaled y ticks=false,
    legend style={at={(0.5,-0.20)}, anchor=north,legend columns=4},
    cycle list={
        {gray1,fill=gray1,mark=none},
        {gray2,fill=gray2,mark=none},
        {gray3,fill=gray3,mark=none},
        {gray4,fill=gray4,mark=none},
        {bronze1,fill=bronze1,mark=none},
        {bronze2,fill=bronze2,mark=none},
        {bronze3,fill=bronze3,mark=none},
        {bronze4,fill=bronze4,mark=none},
        {green1,fill=green1,mark=none},
        {green2,fill=green2,mark=none},
        {green3,fill=green3,mark=none},
        {green4,fill=green4,mark=none},
    },
    ]
    \addplot table [x=Metrik Nr,y=Small A Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Small B Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Small C Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Small D Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Mid A Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Mid B Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Mid C Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Mid D Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Big A Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Big B Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Big C Prozent] {sample.csv}
    \closedcycle;
    \addplot table [x=Metrik Nr,y=Big D Prozent] {sample.csv}
    \closedcycle;
    \legend{Small A, Small B, Small C, Small D, 
            Mid A, Mid B, Mid C, Mid D, 
            Big A, Big B, Big C, Big D}
\end{axis}
\end{tikzpicture}

\end{document}

Answer 1

So you are searching for something like the following? For details please have a look at the comments in the code.

% used PGFPlots v1.15
\begin{filecontents}{sample.csv}
Metrik Nr;Small A;Small B;Small C;Small D;Mid A;Mid B;Mid C;Mid D;Big A;Big B;Big C;Big D;Gesamt;Small A Prozent;Small B Prozent;Small C Prozent;Small D Prozent;Mid A Prozent;Mid B Prozent;Mid C Prozent;Mid D Prozent;Big A Prozent;Big B Prozent;Big C Prozent;Big D Prozent
1;20.0;0.5;0.5;2.0;0.5;0.5;0.5;0.5;20.0;5.0;5.0;2.0;57;35.0877193;0.877192982;0.877192982;3.50877193;0.877192982;0.877192982;0.877192982;0.877192982;35.0877193;8.771929825;8.771929825;3.50877193
2;10.0;0.5;0.5;0.5;0.5;0.5;0.5;0.5;12.0;20.0;8.0;0.5;54;18.51851852;0.925925926;0.925925926;0.925925926;0.925925926;0.925925926;0.925925926;0.925925926;22.22222222;37.03703704;14.81481481;0.925925926
3;7.00;2.00;2.00;2.00;1.00;1.00;1.00;1.00;20.00;10.00;10.00;2.00;59;11.86440678;3.389830508;3.389830508;3.389830508;1.694915254;1.694915254;1.694915254;1.694915254;33.89830508;16.94915254;16.94915254;3.389830508
\end{filecontents}
\documentclass[border=5pt]{standalone}
\usepackage{xcolor}
    \definecolor{gray1}{HTML}{828d94}
    \definecolor{gray2}{HTML}{9ea6ab}
    \definecolor{gray3}{HTML}{b9bfc3}
    \definecolor{gray4}{HTML}{d4d8db}
    \definecolor{bronze1}{HTML}{bab194}
    \definecolor{bronze2}{HTML}{cec7b3}
    \definecolor{bronze3}{HTML}{e2ded2}
    \definecolor{bronze4}{HTML}{f6f5f1}
    \definecolor{green1}{HTML}{94bab1}
    \definecolor{green2}{HTML}{b3cec7}
    \definecolor{green3}{HTML}{d2e2de}
    \definecolor{green4}{HTML}{f1f6f5}
\usepackage{pgfplots}
    \usetikzlibrary{
        calc,
    }
    \pgfplotsset{
        compat=1.15,
        every x tick label/.append style={
            rotate=45,
            anchor=east,
            yshift=-0.3cm,
        },
        axis lines*=left,
        table/col sep=semicolon,
    }
\begin{document}
\begin{tikzpicture}[
    every pin/.append style={
        node font=\small,
        inner sep=1pt,
    },
    Label/.style={
        coordinate,
        xshift=-1ex,
        pin distance=5ex,
    },
]
    \begin{axis}[
        ymin=0,
        ymax=100,
        xtick={1,2,3},
        xticklabels={Metric 1, Metric 2, Metric 3},
        yticklabel={\pgfmathprintnumber{\tick}\%},      % <-- (simplified)
        stack plots=y,
        cycle list={
            {gray1,fill=gray1,mark=none},
            {gray2,fill=gray2,mark=none},
            {gray3,fill=gray3,mark=none},
            {gray4,fill=gray4,mark=none},
            {bronze1,fill=bronze1,mark=none},
            {bronze2,fill=bronze2,mark=none},
            {bronze3,fill=bronze3,mark=none},
            {bronze4,fill=bronze4,mark=none},
            {green1,fill=green1,mark=none},
            {green2,fill=green2,mark=none},
            {green3,fill=green3,mark=none},
            {green4,fill=green4,mark=none},
        },
        axis on top,        % <-- (added, to draw the axis on top)
    ]

        % draw the plots ...
        \pgfplotsforeachungrouped \i in {14,...,25} {
            \edef\temp{
                \noexpand\addplot table [x=Metrik Nr,y index=\i] {sample.csv}
                    % ... and store coordinates for later position the labels
                    coordinate [pos=0.5] (a\i)
                    coordinate [pos=1.0] (b\i)
                \noexpand\closedcycle
                ;
            }\temp
        }

        % create a dummy coordinates at "zero"
        \coordinate (a13) at (2,0);
        \coordinate (b13) at (3,0);

    \end{axis}

    % create coordinates in the middle of the areas
    % (therefore we need the "zero" dummy coordinates)
    \foreach \i [remember=\i as \lasti (initially 13)] in {14,...,25} {
        \coordinate (c\i) at ($ (a\lasti)!0.5!(a\i) $);
        \coordinate (d\i) at ($ (b\lasti)!0.5!(b\i) $);
    }

    % draw "center labels" in "big areas"
    \foreach \i/\Label in {
        14/Small A,
        22/Big A,
        23/Big B,
        24/Big C%
    } {
        \node [node font=\small] at (c\i) {\Label};
    }

    % draw pins to "small areas" part 1
    %
    % These are easy to draw directly to the right.
    \node [
        Label,
        pin={[%
            name=e18,
            inner sep=1pt,
        ]right:Med A}
    ] at (d18) {};
    \node [Label,pin={right:Big D}] at (d25) {};

    % draw pins to "small areas" part 2
    %
    % This is a bit more complicated, because the segments are that small,
    % that the text would overlap. We could change the angle, but then the
    % pins texts wouldn't be aligned any more.
    % That is why we first draw the text labels relative to the "horizontal"
    % label ...
    \begin{scope}[
        node font=\small,
        every node/.append style={
            inner sep=1pt,
        },
    ]
        \node [anchor=north west] (e17) at (e18.south west) {Small D};
        \node [anchor=north west] (e16) at (e17.south west) {Small C};
        \node [anchor=north west] (e15) at (e16.south west) {Small B};

        \node [anchor=south west] (e19) at (e18.north west) {Med B};
        \node [anchor=south west] (e20) at (e19.north west) {Med C};
        \node [anchor=south west] (e21) at (e20.north west) {Med D};
    \end{scope}

    % ... and then draw the pin lines afterwards
    \foreach \i in {15,16,17,19,20,21} {
        \draw [help lines] ([xshift=-1ex]d\i) -- (e\i.west);
    }

\end{tikzpicture}
\end{document}