Dimension too large while plotting external graphic

I am trying to create a plot using an external graphic. The problem is that the axis extents are very different, so I need to use the unit vector (1,300). When I try to compile, I get the following error:

! Dimension too large.
l.23 \end{axis}


How can I convince pgfplots to do the job without manually fiddling with the scaling and the y tick labels?

Here is my code:

\documentclass{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.12}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
enlargelimits=false,
axis on top,
xlabel={$y$},
ylabel={$x$},
unit vector ratio*=1 300,
width=15cm,
tick align=outside,
x dir=reverse,
]
\end{axis}
\end{tikzpicture}
\end{document}


This is the file img.png:

Adjust height instead of unit vector ratio.

\documentclass{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.12}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
enlargelimits=false,
axis on top,
xlabel={$y$},
ylabel={$x$},
%unit vector ratio*=1 300,
width=15cm,
height=3cm,
tick align=outside,
ytick=\empty,   %% y tick doesn't make sense for such a graph
x dir=reverse,
]