\subsection{Using GAIA from IRAF}

GAIA can be run from the IRAF command language, {\tt cl} (see
\xref{SG/12}{sg12}{}\cite{SG12} for an introduction to IRAF on Starlink
systems).  However, before this option is available the GAIA package must
have been included in the version of IRAF that you are using.  This
customisation will usually already have been performed if you are using
IRAF at a Starlink site.

Assuming that the IRAF GAIA package is available, your first step must
be to initialise it.  From the IRAF {\tt cl} type:

\begin{quote}
{\tt cl>  gaia}
\end{quote}

(Alternatively, if you think that you will often want to use GAIA from
within IRAF, then you could include this step in your IRAF {\tt login.cl}
file.)

To display an image type:

\begin{quote}
{\tt cl>  gaiadisp} {\it image ~plane-number}
\end{quote}

{\it image}\/ is the image to be displayed and {\it plane-number}\/ is
the number of the IRAF display plane in which the image is to appear
(which is identical to the GAIA clone number).  For example:

\begin{quote}
{\tt cl>  gaiadisp ~dev\$pix.imh ~1}
\end{quote}

will display the default IRAF image in display plane 1.  The image will
either be displayed into an existing GAIA window, or a new window will
be created, as required.  Note that because GAIA is not a native IRAF
image display task it does not support any of the IRAF cursor commands.

