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如何绘制连接轴环境中的节点的线？

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如何绘制连接轴环境中的节点的线？

我正在尝试绘制类似的箭头线(A) -> (A1) -> (A2) -> (A3)，但我的代码不起作用。

\documentclass[11pt,a4paper]{article}
\usepackage{geometry}
\usepackage{tikz}
\usepackage{pgfplots, relsize}
\usepgfplotslibrary{polar}
\usepgflibrary{shapes.geometric}
\usetikzlibrary{calc}

\usetikzlibrary{arrows,decorations.markings}
\begin{document}

\begin{center}
\begin{tikzpicture}
  \begin{axis}[
  unit vector ratio*=1 1 1,
   grid = none,
    axis x line = middle,
    axis y line = middle,
    xlabel={$k_t$},
    xlabel style={at=(current axis.right of origin), anchor=west},
    ylabel={$k_{t+1}$},
    ylabel style={at=(current axis.above origin), anchor=south},
    xmin = 0,
    xmax = 15,
    scale=1.5,
    enlarge y limits={rel=0.13},
    enlarge x limits={rel=0.07},
    ymin = 0,
    ymax = 10,  xtick=\empty,ytick=\empty,
    after end axis/.code={\path (axis cs:0,0) node [anchor=north west] {0};},
  ]
    \coordinate (0,0) ;
    % domain can be set individually!!
    \addplot[color=red, domain=0:10,samples=100,smooth,thick] {x} node[above,pos=1] {$45^\circ$};
    \addplot[color=blue,domain=0:11,samples=1000,smooth, thick] {3*sqrt(x)} node[right,pos=1] {$W(s,k_{t},\delta)$};
    \addplot[color=Cerulean,domain=0:11,samples=1000,smooth, thick] {2*sqrt(x)} node[right,pos=1] {$W(s',k_{t},\delta)$};

    \addplot[mark=*,only marks, fill=white] coordinates {(9,9)} node[above, pos=1]{$A$};
    \addplot[mark=*,only marks, fill=white] coordinates {(4,4)} node[above, pos=1]{$A'$};

    \addplot[mark=*,only marks, fill=white] coordinates {(9,6)} node[below, pos=1]{$A_1$};
    \addplot[mark=*,only marks, fill=white] coordinates {(6,6)} node[above, pos=1]{$A_2$};
    \addplot[mark=*,only marks, fill=white] coordinates {(6,4.899)} node[below, pos=1]{$A_3$};
    \addplot[mark=*,only marks, fill=white] coordinates {(4.899,4.899)} node[above, pos=1]{$A_4$};

    % NO output shown at all
    \node (A) at (9, 9){};
    \node (Ap) at (4, 4){};
    \node (A1) at (9, 6){};
    \node (A2) at (6, 6){};
    \node (A3) at (6, 4.899){};
    \node (A4) at (4.899, 4.899){};
    \draw [dashed] (A) -- (A1) -- (A2) -- (A3) -- (A4);
  \end{axis}

\end{tikzpicture}
\end{center}
\end{document}

在此处输入图片描述

输出严重不成比例（如果您找不到它，它是原点附近的小虚线）。位置和比例完全偏离。有趣的是，当我将声明\node和\draw语句放在外面时{axis}，输出再次偏离，但偏离的方向相反。我相信我没有\node正确定义与{axis}坐标相关的对象，它们都位于其他坐标系中。

有办法解决这个问题吗？谢谢！

答案1

这仅是对多个箭头部分的回答。Stefan Pinnow 已经指出，应该使用较新版本的 pgfplots 兼容性。在这里，我展示了如何通过 (ab) 使用 来绘制多个箭头show path construction。

\documentclass[11pt,a4paper]{article}
\usepackage{geometry}
\usepackage{tikz}
\usepackage{pgfplots, relsize}
\usepgfplotslibrary{polar}
\usepgflibrary{shapes.geometric}
\usetikzlibrary{calc}
\pgfplotsset{compat=1.16}
\usetikzlibrary{arrows,decorations.markings,decorations.pathreplacing}
\begin{document}

\begin{center}
\begin{tikzpicture}
  \begin{axis}[
  unit vector ratio*=1 1 1,
   grid = none,
    axis x line = middle,
    axis y line = middle,
    xlabel={$k_t$},
    xlabel style={at=(current axis.right of origin), anchor=west},
    ylabel={$k_{t+1}$},
    ylabel style={at=(current axis.above origin), anchor=south},
    xmin = 0,
    xmax = 15,
    scale=1.5,
    enlarge y limits={rel=0.13},
    enlarge x limits={rel=0.07},
    ymin = 0,
    ymax = 10,  xtick=\empty,ytick=\empty,
    after end axis/.code={\path (axis cs:0,0) node [anchor=north west] {0};},
  ]
    \coordinate (0,0) ;
    % domain can be set individually!!
    \addplot[color=red, domain=0:10,samples=100,smooth,thick] {x} node[above,pos=1] {$45^\circ$};
    \addplot[color=blue,domain=0:11,samples=1000,smooth, thick] {3*sqrt(x)} node[right,pos=1] {$W(s,k_{t},\delta)$};
    \addplot[color=cyan,domain=0:11,samples=1000,smooth, thick] {2*sqrt(x)} node[right,pos=1] {$W(s',k_{t},\delta)$};

    \addplot[mark=*,only marks, fill=white] coordinates {(9,9)} node[above, pos=1]{$A$};
    \addplot[mark=*,only marks, fill=white] coordinates {(4,4)} node[above, pos=1]{$A'$};

    \addplot[mark=*,only marks, fill=white] coordinates {(9,6)} node[below, pos=1]{$A_1$};
    \addplot[mark=*,only marks, fill=white] coordinates {(6,6)} node[above, pos=1]{$A_2$};
    \addplot[mark=*,only marks, fill=white] coordinates {(6,4.899)} node[below, pos=1]{$A_3$};
    \addplot[mark=*,only marks, fill=white] coordinates {(4.899,4.899)} node[above, pos=1]{$A_4$};

    % NO output shown at all
    \node (A) at (9, 9){};
    \node (Ap) at (4, 4){};
    \node (A1) at (9, 6){};
    \node (A2) at (6, 6){};
    \node (A3) at (6, 4.899){};
    \node (A4) at (4.899, 4.899){};
    \draw [decorate,decoration={show path construction,
lineto code={\draw[dashed,-latex] (\tikzinputsegmentfirst) -- (\tikzinputsegmentlast); }}]
(A) -- (A1) -- (A2) -- (A3) -- (A4);
  \end{axis}

\end{tikzpicture}
\end{center}
\end{document}

在此处输入图片描述

答案2

正如前面提到的在问题下方评论节点“位移”是因为您（意外地）为 TikZ 坐标使用了错误的坐标系。为了避免这种情况，可以\pgfplotsset{compat=1.11}在前言中声明（或更高的值），或者在前面加上 TikZ 坐标，axis cs:否则将使用tikzpicture坐标而不是坐标axis。

这里我提出了一个“干净”的尝试来实现你想要的，而不需要重复，而且这也不需要上述的东西。正如 marmot 已经在他在这个问题下的评论你可以利用edge画出带箭头的连接线，但我借用decoration了他的回答这好多了。

% used PGFPlots v1.16
\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
    \usetikzlibrary{decorations.pathreplacing}
    \pgfplotsset{
        % declare the style of the marks/nodes here (once)
        points/.style={
            mark=*,
            only marks,
            fill=white,
        },
    }
\begin{document}
\begin{tikzpicture}
    \begin{axis}[
        axis lines=middle,
        xlabel={$k_t$},
        xlabel style={
            at=(current axis.right of origin),
            anchor=west,
        },
        ylabel={$k_{t+1}$},
        ylabel style={
            at=(current axis.above origin),
            anchor=south,
        },
        xmin=0,
        xmax=15,
        scale=1.5,
        enlarge y limits={rel=0.13},
        enlarge x limits={rel=0.07},
        ymin=0,
        ymax=10,
        xtick=\empty,
        ytick=\empty,
        after end axis/.code={
            \path (0,0) node [anchor=north west] {0};
        },
        % ---------------------------------------------------------------------
        % moved common `\addplot' options here
        smooth,
        % there is no need to use that many coordinates
        % (to further decrease them you can adapt use "non-linear spacing"
        %  between the points as e.g. shown at
        %  <https://tex.stackexchange.com/a/373820/95441>)
        samples=201,
        domain=0:11,
    ]
        \addplot [red,thick,domain=0:10,samples=2] {x}
            node [above] {$45^\circ$}
        ;
        \addplot [blue,thick] {3*sqrt(x)}
            node [right] {$W(s,k_{t},\delta)$}
        ;
        \addplot [green,thick] {2*sqrt(x)}
            node [right] {$W(s',k_{t},\delta)$}
        ;

        \addplot [
            points,
            % specify the points where the points should be shown ...
            samples at={4,4.899,6,9},
        ] {x}
            % ... and add nodes with labels accordingly
            node [pos=0.00,label=$A'$]  (Ap) {}
            node [pos=0.25,label=$A_4$] (A4) {}
            node [pos=0.50,label=$A_2$] (A2) {}
            node [pos=1.00,label=$A$]   (A)  {}
        ;
        \addplot [
            points,
            samples at={6,9},
        ] {2*sqrt(x)}
            node [pos=0,label=below:$A_3$] (A3) {}
            node [pos=1,label=below:$A_1$] (A1) {}
        ;

        % draw the connecting line between the points
        \draw [
            decorate,
            decoration={
                show path construction,
                lineto code={
                    \draw [dashed,-latex]
                        (\tikzinputsegmentfirst) -- (\tikzinputsegmentlast)
                    ;
                }
            },
        ] (A) -- (A1) -- (A2) -- (A3) -- (A4);
    \end{axis}
\end{tikzpicture}
\end{document}

该图显示了上述代码的结果

答案3

您必须使用axis cs坐标系来指定 pgfplots 中轴内的点。还有其他几个坐标系可供使用（请参阅手册），但就您而言，这是您需要的坐标系。
因此，您的代码变为（我省略了未更改的部分）

\node (A) at (axis cs:9, 9){};
\node (Ap) at (axis cs:4, 4){};
\node (A1) at (axis cs:9, 6){};
\node (A2) at (axis cs:6, 6){};
\node (A3) at (axis cs:6, 4.899){};
\node (A4) at (axis cs:4.899, 4.899){};
\draw [dashed] (A) -- (A1) -- (A2) -- (A3) -- (A4);

为了改变使用的坐标系，必须在第一个坐标规范前面加上相应的名称和冒号，就像我在给定的例子中所做的那样。

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