pgfplots：不同尺度上的轴相等

Question

我有：

我必须设置什么，x 单位（0,1,2，...，24）具有与 y 单位（100，...，800）的高度相同的宽度。

这样网格的矩形就变成了正方形，就像这样

有没有什么

%axis equal, 
%unit vector ratio=1 1,
%x=0.1cm*3, y=0.001cm*3,

梅威瑟：

\documentclass[border=5pt, tikz]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepackage{siunitx}
\sisetup{per-mode=fraction,
%fraction-function=\tfrac
}

\begin{document}
\begin{tikzpicture}[font=\footnotesize,
]
\begin{axis}[
xlabel={$t\, [\si{\hour}]$},
ylabel={$\displaystyle f(t)\, \left[   \si{\metre\cubed\per\hour} \right]$},
title={$f(t)=\frac14 t^3 -12t^2 +144t +250$},
axis lines=middle, % so kein Ursprung
axis x line=bottom,  % so ein Ursprung
%axis equal, 
%unit vector ratio=1 1,
%x=0.1cm*3, y=0.001cm*3,
xmin=0, xmax=25.5,
ymin=0, ymax=800,
xtick={0,2,...,24},
ytick={100,200,...,800},
xlabel style={anchor= south east},
ylabel style={anchor= north west},
grid=major, 
%enlarge x limits={abs=1.1, upper},
enlarge y limits={rel=0.1, upper},
]
\addplot[thick, smooth, samples=222, domain=0:25, variable=\t] {0.25*t^3-12*t^2+144*t+250};
\end{axis}
\end{tikzpicture}
\end{document}

Answer 1

如果您希望 x 轴上的分割（即 13）与 y 轴上的分割（即 8）具有相同的大小，您可以执行以下操作：

1. 删除轴的自动缩放，例如enlarge y limits
2. 使用scale only axis，它将适用width于length轴
3. 选择与分区数成比例的垂直和水平宽度。

\documentclass[border=5pt, tikz]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepackage{siunitx}
\sisetup{per-mode=fraction,
%fraction-function=\tfrac
}

\begin{document}
\begin{tikzpicture}[font=\footnotesize,
]
\begin{axis}[
xlabel={$t\, [\si{\hour}]$},
ylabel={$\displaystyle f(t)\, \left[   \si{\metre\cubed\per\hour} \right]$},
title={$f(t)=\frac14 t^3 -12t^2 +144t +250$},
axis lines=middle, % so kein Ursprung
axis x line=bottom,  % so ein Ursprung
scale only axis, 
% 6.15cm = 10cm * hor_division * vert_divisions =10cm/13*8 
width=10cm, height=6.15cm,
xmin=0, xmax=26,
ymin=0, ymax=800,
xtick={0,2,...,26},
ytick={100,200,...,800},
xlabel style={anchor= south east},
ylabel style={anchor= north west},
grid=major, 
]
\addplot[thick, smooth, samples=222, domain=0:25, variable=\t] {0.25*t^3-12*t^2+144*t+250};
\end{axis}
\end{tikzpicture}
\end{document}

Answer 2

我用这种方法解决了：

\pgfmathsetlengthmacro\u{6.5mm}

进而

x=0.5*\u, y=0.01*\u

\documentclass[border=5pt, tikz]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepackage{siunitx}
\sisetup{per-mode=fraction,
%fraction-function=\tfrac
}

\pgfmathsetlengthmacro\u{6.5mm}

\begin{document}
\begin{tikzpicture}[font=\footnotesize,
]
\begin{axis}[
xlabel={$t\, [\si{\hour}]$},
ylabel={$\displaystyle f(t)\, \left[   \si{\metre\cubed\per\hour} \right]$},
title={$f(t)=\frac14 t^3 -12t^2 +144t +250$},
axis lines=middle, % so kein Ursprung
axis x line=bottom,  % so ein Ursprung
x=0.5*\u, y=0.01*\u,
xmin=0, xmax=25.5,
ymin=0, ymax=800,
xtick={0,2,...,24},
ytick={100,200,...,800},
xlabel style={anchor= south east},
ylabel style={anchor= north west},
grid=major, 
%enlarge x limits={abs=1.1, upper},
enlarge y limits={rel=0.1, upper},
]
\addplot[thick, smooth, samples=222, domain=0:25, variable=\t] {0.25*t^3-12*t^2+144*t+250};
\end{axis}
\end{tikzpicture}
\end{document}