PGFPlots – Positioning ‘Node Near Coord’ at Bottom of Bar

Question

I would like to position nodes near coords at the bottom of the corresponding bar, right by the X axis.

Here's what I've got now:

\documentclass{report}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
    \begin{axis}[
            ybar,
            ymin=0, yticklabel style={/pgf/number format/fixed},
            symbolic x coords={0,1,2,3}, enlarge x limits=0.15,
            every node near coord/.append style={font=\tiny, yshift=-30}]        
        \addplot+ [nodes near coords, point meta=explicit symbolic]
            table[x index=0, y index=1, meta index=3] {
                0   0.1872  0.0040  0
                1   0.0358  0.0017  22
                2   0.0358  0.0017  23
                3   0.0358  0.0017  24
            };
    \end{axis}
\end{tikzpicture}
\end{document}

I assume if I could write something like yshift=\getcurrentvalueofy (or yshift=\getbarheight), the problem would be solved. I tried \pgfkeysvalueof{/data point/y}, but I must admit I did not really understand what I was doing, so it did not work out.

Answer 1

You can make the value of the y coordinate available using the key visualization depends on=y \as \rawy (where \rawy is a macro name you choose). Then you can shift the nodes using shift={(axis direction cs:0,-\rawy)}. Note that you'll have to use axis direction cs because the coordinate system is shifted and scaled at the time when the nodes are placed.

\documentclass{report}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
    \begin{axis}[
            ybar,
            ymin=0, yticklabel style={/pgf/number format/fixed},
            visualization depends on=y \as \rawy,
            symbolic x coords={0,1,2,3}, enlarge x limits=0.15,
            every node near coord/.append style={
                    font=\tiny,
                    shift={(axis direction cs:0,-\rawy)}
                }
        ]        
        \addplot+ [nodes near coords, point meta=explicit symbolic]
            table[x index=0, y index=1, meta index=3] {
                0   0.1872  0.0040  0
                1   0.0358  0.0017  22
                2   0.0358  0.0017  23
                3   0.0358  0.0017  24
            };
    \end{axis}
\end{tikzpicture}
\end{document}