如何在图表中添加误差线？

Question

我将尝试解释为什么它会令人困惑，我需要在图表中放置一些误差线。有什么想法我该怎么做吗？

\begin{document}

\begin{figure}
  \begin{subfigure}{0.31\textwidth}
    \centering
\begin{tikzpicture}
\begin{axis}
    [name=plot,
    ymin=1.8,ymax=2.7,xmin=0.45,xmax=0.7
  ,
    xlabel = $L(m)$,
    ylabel = {$T^2(s^2)$},
    legend pos=north west,
    scatter/classes={%
    a={mark=o,draw=black}}]
\addplot[scatter,only marks,%
    scatter src=explicit symbolic]%
table[meta=label] {
x y label
0.650  2.6 a
0.606 2.4 a
0.581 2.4 a
0.555 2.3 a
0.526 2.16 a 
0.502 2 a   
};\label{puntos}
    ]

\addplot [
    color=red,
]
{x*3.7844+0.1529};\label{Func2}


\end{axis}
 \node[anchor=north west, draw=black, fill=white] (legend) at (plot.north west) {\begin{tabular}{l l}
 Ajuste & \ref{Func2}\\
 Datos & \ref{puntos}
\end{tabular}};
\end{tikzpicture}
    \caption{First subfigure} \label{fig:1a}
  \end{subfigure}%
\end{figure}

Answer 1

好的，我想你想要一个绝对y 误差在两个方向（即正和负）的值为 0.08（而不是 0.8）。这很容易实现。

% used PGFPlots v1.17
\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
    \begin{axis}[
        xmin=0.45,
        xmax=0.7,
        ymin=1.8,
        ymax=2.7,
        xlabel=$L (m)$,
        ylabel={$T^2 (s^2)$},
        legend pos=north west,
        scatter/classes={%
            a={mark=o,draw=black}%
        },
    ]
        \addplot [
            scatter,
            only marks,
            scatter src=explicit symbolic,
            % ---------------
            % added stuff
            error bars/.cd,
                y dir=both,
                y fixed=0.08,
            % ---------------
        ] table [meta=label] {
            x       y       label
            0.650   2.6     a
            0.606   2.4     a
            0.581   2.4     a
            0.555   2.3     a
            0.526   2.16    a
            0.502   2       a
        };
        \addplot [red] {x*3.7844+0.1529};

        % (simplified your legend)
        \legend{
            Ajuste,
            Datos,
        }
    \end{axis}
\end{tikzpicture}
\end{document}