This is a follow-up question to this one.
Here is a MWE showing the problem:
\documentclass[tikz]{standalone}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{pgfplots}
\usepackage{grffile}
\pgfplotsset{compat=newest}
\usetikzlibrary{plotmarks}
\usetikzlibrary{arrows.meta}
\usepgfplotslibrary{patchplots}
\usepackage{amsmath}
\begin{document}
\begin{tikzpicture}
\begin{axis}[%
width=5.167in,
height=3.622in,
at={(0.867in,0.489in)},
scale only axis,
separate axis lines,
every outer x axis line/.append style={black},
every x tick label/.append style={font=\color{black}},
xmin=0,
xmax=1,
every outer y axis line/.append style={black},
every y tick label/.append style={font=\color{black}},
ymin=0,
ymax=0.45,
axis background/.style={fill=white}
]
\addplot[%
point meta={sqrt((\thisrow{u})^2+(\thisrow{v})^2)},
quiver={u=\thisrow{u},v=\thisrow{v},
every arrow/.append style={-{Straight Barb[scale length={max(0.01,\pgfplotspointmetatransformed/1000)},scale width={0.5*max(0.01,\pgfplotspointmetatransformed/1000)}]}}}
]
table[row sep=crcr]{
%
x y u v\\
0 0 0.45 0.45\\
1 0 -0.45 0.45\\
};
\end{axis}
\end{tikzpicture}%
\end{document}
And here is the output:
The problem is that the arrowheads are extremely small!
max(0.01, ...
tomax(10, ...
\pgfplotspointmetatransformed
defaults to 0?point meta min=0
makes sure that\pgfplotspointmetatransformed
isn't 0 when the arrow length is non-zero. To get reasonable sized arrows I still need to add a scaling factor on the computed length though.