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用线性线注释图

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用线性线注释图

在下面的代码中，我想添加一条像这样的线性虚线：

在此处输入图片描述 这是我的代码：

\documentclass[varwidth]{standalone}
\usepackage{filecontents}
\usepackage{graphicx}
\usepackage{tikz}
\usepackage{float}
\usepackage{pgfplots,pgfplotstable, booktabs}
\pgfplotsset{compat=1.12}
\usetikzlibrary{pgfplots.groupplots, matrix, backgrounds}
\usepgfplotslibrary{fillbetween}

\pgfplotsset{compat=1.12}
\pgfplotsset{minor grid style={dotted,gray!50}}
\pgfplotsset{major grid style={gray!50!black},
             every tick label/.append style={scale=0.85}}

\begin{filecontents*}{testdata.csv}
-155.5  21.7
-152.3  21.5
-149.8  21.2
-147.2  20.8
-145.5  20.3
-143.7  19.5
-141.3  18.4
\end{filecontents*}

\begin{document}
\begin{figure}[H]
\centering
\begin{tikzpicture}[every plot/.append style={very thick}]
\begin{axis}[width=14cm,height=9cm,
                    grid = both,
                    every major grid/.style={gray, opacity=0.7},
                    x dir=reverse,
                    title = {},
                    xlabel={Time},
                    ylabel={Temp},
                    ]

\addplot+ [smooth,blue,name path=plotA] table[mark = none, x index=0,y index=1,col sep=space] {testdata.csv};
\draw [-latex] (-143,21.3) node[above,text width=.8cm,align=center]{\scriptsize{end of \\ linear region}} to[out=270,in=130] (-145,20.1);
\end{axis}
\end{tikzpicture}
\end{figure} 
\end{document}

答案1

您可以向图中添加坐标，如下所示：

\addplot+ [smooth,blue,name path=plotA] table[mark = none, x index=0,
y index=1,col sep=space] {testdata.csv}%
    coordinate [pos=1] (A)
    coordinate [pos=0.9] (B);

1是线的末端，0是起点。因此，我们选择两个构成一条线的点，然后使用 的负值使其更长shorten，例如

\draw[red,loosely dashed, very thick,shorten >=-7cm] (A) -- (B);

这是输出

在此处输入图片描述

答案2

(-143.7,19.5)我已经计算了具有和点的线性方程(-141.3,18.4)，并得到了以下近似值：y=-0.45833333333333*x-46.3625。然后，将其输入到您的tikzpicture：\addplot+[red,dashed,mark=no,domain=-141.3:-147.75]{-0.45833333333333*x-46.3625};

完整代码：

\documentclass[varwidth]{standalone}
\usepackage{filecontents}
\usepackage{graphicx}
\usepackage{tikz}
\usepackage{float}
\usepackage{pgfplots,pgfplotstable, booktabs}
\pgfplotsset{compat=1.12}
\usetikzlibrary{pgfplots.groupplots, matrix, backgrounds}
\usepgfplotslibrary{fillbetween}

\pgfplotsset{compat=1.12}
\pgfplotsset{minor grid style={dotted,gray!50}}
\pgfplotsset{major grid style={gray!50!black},
             every tick label/.append style={scale=0.85}}

\begin{filecontents*}{testdata.csv}
-155.5  21.7
-152.3  21.5
-149.8  21.2
-147.2  20.8
-145.5  20.3
-143.7  19.5
-141.3  18.4
\end{filecontents*}

\begin{document}
\begin{figure}[H]
\centering
\begin{tikzpicture}[every plot/.append style={very thick}]
\begin{axis}[width=14cm,height=9cm,
                    grid = both,
                    every major grid/.style={gray, opacity=0.7},
                    x dir=reverse,
                    title = {},
                    xlabel={Time},
                    ylabel={Temp},
                    ]

\addplot+ [smooth,blue] table[mark = none, x index=0,y index=1,col sep=space] {testdata.csv};
\draw [-latex] (-143,21.3) node[above,text width=.8cm,align=center]{\scriptsize{end of \\ linear region}} to[out=270,in=130] (-145,20.1);
\addplot+[red,dashed,mark=no,domain=-141.3:-147.75]{-0.45833333333333*x-46.3625};
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}

输出 ：

在此处输入图片描述

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