PGFPLOTS 标签放置

Question

和往常一样，有多种方法可以做到这一点。这里是其中一种方法。一些评论。

（A）可能有一种方法可以通过 pgfplots 选项和命令实现所有功能。但是，我发现尝试所有功能非常繁琐。// 因此，让我们Inventive Thinking以（待解释）的形式应用一些Inventive Principles (IP)。

（二） Making a copy (of addplot)+ Taking out (data)。复制整个\addplot语句并相互删除数据很容易。这样，您将有机会以您想要的方式（即以不同的方式）处理两个图。 // 再次，尝试所有 pgfplots 选项还不够快，所以让我们再应用另一个IP。

（C） Do a little more (coding)。那么，为什么不把几个有问题的数据点放在\addplot（上面已经做过了）上，并把一些放在\node缺失的标签上呢？//为了更好地看到它们，我给它们涂上了颜色red。你可以看到各种锚定或移动标签的方法。做出你的选择。（是的，你可以用替换所有内容\foreach，但代码不会很短，可能不那么容易理解。）

...
    % ~~~ Inventive Principle: Do a little more (coding) ~~~~~~~~~~~
    % ~~~ Poor mans solution: place those labels manually ~~~~~~~
    \node[red,anchor=west] at (7.2,.7){\ce{Cr}};% using standard names
    \node[red,anchor=160]  at (7.2,.5){\ce{Fe}};% using polar notation
...

（四）好吧，放置轴标签的工作就留给你了 ;-)

（英）另外，您还可以将彩色区域和虚线分配给另一个\addplot，该另一个应该是第一个。这样，您就不需要\node在代码末尾添加 s ( IP: Improve by total replacement)。

\documentclass[border=6pt,dvipsnames]{standalone}
\usepackage[T1]{fontenc}
\usepackage[main=french, english]{babel}
\usepackage[version=4]{mhchem}
\usepackage{pgfplots}
\pgfplotsset{compat=1.17}
\usetikzlibrary{babel, backgrounds}
\usepackage[dvipsnames]{xcolor}

\begin{document}

\begin{tikzpicture}
  \begin{axis}[xmin=0, xmax=8, ymin=0, ymax=5,%
  % ~~~ these puzzle me, so take them away for the moment ~~~~~
%%    xlabel near ticks, 
%    xlabel={Economic importance},%
%%    ylabel near ticks, 
%    ylabel={Supply risk},%
%    axis lines=middle,%
    xtick={0, 2.8, 8},%
    ytick={0, 1.0, 5},%
    unit vector ratio={5 8}
    ]
    % ~~~ See next comment for modifications done ~~~~~~~~~
    \addplot[
      scatter/classes={%
        CRM={mark=*},%
        SRM={fill=gray, mark=*},%
        non={scale=.5,mark=*}},
      scatter, only marks, 
      scatter src=explicit symbolic,
      nodes near coords*={\Label},
      visualization depends on={value \thisrow{label} \as \Label}
    ] table [meta=class] {
        EI  SR  class label
        4.9 4.0  CRM  \ce{Ce}
        6.8 2.8  CRM  \ce{Co}
        4.0 0.1  SRM  \ce{Cu}
        6.4 3.9  CRM  \ce{Ir}
        5.7 0.5  SRM  \ce{Ni}
        6.9 2.1  CRM  \ce{Pt}
        6.3 1.6  CRM  \ce{Ti}
    };
    % ~~~ Inventive Principles: Making a copy (of addplot) + Taking out (data) ~~~~~~~~~
    \addplot[
      scatter/classes={%
        CRM={mark=*},%
        SRM={fill=gray, mark=*},%
        non={scale=.5,mark=*}},
      scatter, only marks, 
      scatter src=explicit symbolic,
%      nodes near coords*={\Label},
%      visualization depends on={value \thisrow{label} \as \Label},
      label distance=1cm,
    ] table [meta=class] {
        EI  SR  class label
        7.2 0.7  non  \ce{Cr}
        7.2 0.5  non  \ce{Fe}
        6.9 1.2  CRM  \ce{Mn}
        6.7 0.8  non  \ce{Mo}
        2.9 0.5  non  \ce{H}
        2.9 3.5  CRM  \ce{La}
    };
    % ~~~ Inventive Principle: Do a little more (coding) ~~~~~~~~~~~
    % ~~~ Poor mans solution: place those labels manually ~~~~~~~
    \node[red,anchor=west] at (7.2,.7){\ce{Cr}};% using standard names
    \node[red,anchor=160]  at (7.2,.5){\ce{Fe}};% using polar notation
    \node[red,anchor=200]  at (6.9,1.2){\ce{Mn}};
    \node[red,anchor=70 ]  at (6.7,.8){\ce{Mo}};
    \node[red,anchor=250]  at (2.9,.5){\ce{H}};
    \node[red,xshift=3mm]  at (2.9,3.5){\ce{La}};% alternative way to place labels

    % ~~~ unchanged ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    \node (O) at (0,0) {};
    \node (A) at (2.8,0 |- current axis.south) {};
    \node (B) at (2.8,0 |- current axis.north) {};
    \node (C) at (current axis.west |- 0,1.0) {};
    \node (D) at (current axis.east |- 0,1.0) {};
    \node (M) at (A |- C) {};
    \node (X) at (D |- B) {};
    \begin{scope}[on background layer]
      \fill[gray!5] (O) rectangle (X);
      \fill[red!20] (M) rectangle (X);
      \draw[dashed] (A)--(B);
      \draw[dashed] (C)--(D);
    \end{scope}
  \end{axis}
\end{tikzpicture}

\end{document}

Answer 1