pgfplots - Provide a detailed plot inside the main plot

Question

I have a main plot and inside it I would like to add a smaller plot that offers a higher level of detail.

A rough illustration of the above is:

Notice that the smaller plot provides a more detailed evolution of the blue curve when the latter approaces the x-axis.

How can I do that using the pgfplots package?

Answer 1

I'm not sure why the spy library isn't suitable, but you can achieve what you want by using

\newsavebox{\mybox}
\savebox{\mybox}{%
      <code for miniature figure>
}

and then \usebox{\mybox} at an appropriate place on the axis. Note that you can't use a node directly as pgfplots won't allow you to nest axis.

% arara: pdflatex
\documentclass{standalone}
\usepackage{pgfplots}

\begin{document}

\newsavebox{\mybox}
\savebox{\mybox}{%
\begin{tikzpicture}
  \begin{axis}[xmin=0,xmax=25,
               ymin=0,ymax=1,
               grid=both,
               width=6cm,
               height=3cm]
               \addplot expression[domain=1:25,red,mark=none,very thick]{sin(deg(1/x))};
  \end{axis}
\end{tikzpicture}
}

\begin{tikzpicture}
  \begin{axis}[xmin=0,xmax=25,
               ymin=0,ymax=1,
               grid=both]
               \addplot expression[domain=1:25]{sin(deg(1/x))};
               \draw (axis cs: 13,.4)node{\usebox{\mybox}};
  \end{axis}
\end{tikzpicture}

\end{document}