如何给散点图中的点添加标签

Question

我正在尝试在 tikz 中标记散点图上的点。例如对于蓝色方块点，我想在绘图本身上在其旁边添加一个标签。类似于在蓝色方块旁边添加一个标签，上面写着“3x5”，而在红色方块旁边添加一个标签，上面写着“3x10”。我可以用我的代码做到这一点吗？谢谢

代码：

\documentclass[tikz, border=1cm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.18}

\begin{document}

\begin{tikzpicture}

\pgfplotsset{
  set layers,% using layers
  mark layer=axis tick labels% defines the layer of the marks
}

\begin{loglogaxis}[
xmin=0, xmax=1e7,
ymin=1e-4, ymax=1e3,
xlabel={Number of Epochs}, 
ylabel={Normalized MSE: $\log_{10} (e)$ },
label style={font=\bfseries\boldmath},
tick label style={font=\bfseries\boldmath},
scatter/classes={ a={mark=square*, blue}, b={mark=square*, red}, c={mark=square, black}, d={mark=triangle*, blue}, e={mark=triangle*, red},f={mark=triangle*, black},g={mark=x, black}, h={mark= diamond*, pink} },
] 
\addplot[scatter, only marks,
scatter src=explicit symbolic]
table[meta=label] {
x     y      label
320 0.608216725 a
500 0.522425565 b
1100    0.362002313 c
3260    0.03403538 a 
11420   0.002463198 b
43100   0.000725737 c


};

\end{loglogaxis}
\end{tikzpicture}

\end{document}

Answer 1

如果您想为每个节点添加标签，最好在表中添加另一列，其中包含这些标签的值。然后，您可以使用visualization depends on和nodes near coords*选项的组合来访问这些值，如以下示例所示。

\documentclass[border=1cm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.18}

\begin{document}
\begin{tikzpicture}

\begin{loglogaxis}[
    %xmin=0, 
    xmax=1e7,
    ymin=1e-4, 
    ymax=1e3,
    xlabel={Number of Epochs}, 
    ylabel={Normalized MSE: $\log_{10} (e)$},
    label style={font=\bfseries\boldmath},
    tick label style={font=\bfseries\boldmath},
    scatter/classes={
        a={mark=square*, blue}, 
        b={mark=square*, red}, 
        c={mark=square, black}, 
        d={mark=triangle*, blue}, 
        e={mark=triangle*, red},
        f={mark=triangle*, black},
        g={mark=x, black}, 
        h={mark= diamond*, pink}
    },
] 

\addplot[
        scatter, 
        only marks,
        scatter src=explicit symbolic,
        nodes near coords*={\annotvalue},
        node near coord style={rotate=45, anchor=south west, font=\scriptsize},
        visualization depends on={value \thisrow{annotation} \as \annotvalue},
    ]
    table[meta=label] {
        x       y            label  annotation
        320     0.608216725  a      $3\times5$
        500     0.522425565  b      $3\times10$
        1100    0.362002313  c      $3\times10$
        3260    0.03403538   a      $3\times5$
        11420   0.002463198  b      $3\times10$
        43100   0.000725737  c      $3\times5$
    };

\end{loglogaxis}

\end{tikzpicture}
\end{document}

请注意，使用时visualization depends on，只有当表中存在相应值时，相关宏才会更新。因此，如果您想省略标签，则需要将\null相关条目添加到表中。

---

另一种方法是添加图例：

\documentclass[border=1cm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.18}

\begin{document}
\begin{tikzpicture}

\begin{loglogaxis}[
    %xmin=0, 
    xmax=1e7,
    ymin=1e-4, 
    ymax=1e3,
    xlabel={Number of Epochs}, 
    ylabel={Normalized MSE: $\log_{10} (e)$},
    label style={font=\bfseries\boldmath},
    tick label style={font=\bfseries\boldmath},
    scatter/classes={
        a={mark=square*, blue}, 
        b={mark=square*, red}, 
        c={mark=square, black}, 
        d={mark=triangle*, blue}, 
        e={mark=triangle*, red},
        f={mark=triangle*, black},
        g={mark=x, black}, 
        h={mark= diamond*, pink}
    },
] 

\addplot[
        scatter, 
        only marks,
        scatter src=explicit symbolic
    ]
    table[meta=label] {
        x       y            label
        320     0.608216725  a
        500     0.522425565  b
        1100    0.362002313  c
        3260    0.03403538   a
        11420   0.002463198  b
        43100   0.000725737  c
    };

\legend{$3\times5$, $3\times10$, $3\times15$}

\end{loglogaxis}

\end{tikzpicture}
\end{document}