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<H2><A NAME="SECTION001011000000000000000"> </A>
<A NAME="plot-introduction"> </A>
<BR>
Introduction
</H2>
In order to provide a device-independent graphics package, the Italian
Astronet Graphic Library has been adopted as the standard low level
library for the plot package in MIDAS. One of the main reasons for using
the AGL package rather than one of the more evolved and sophisticated
packages (<I>e.g.</I> GKS) was the fact that the AGL <A NAME="8094"> </A> package is simple; meanwhile AGL is still capable of
doing the things one needs for reasonably advanced graphics, in particular
with respect to interactive facilities. The AGL graphics library is
fully integrated within the MIDAS directory structure and is generated
like every other MIDAS subroutine library during installation. For an
extensive description of the package we refer to the AGL User's and
Installation Guides for Version 3.
<P>
The graphic facilities available in MIDAS can be divided into three
main categories of commands, based on their functionality:
<UL>
<LI>general plot commands <A NAME="8096"> </A> that deal with
the setup of graphic packages: the assignment of the graphics
device, routing a plot file to a graphic device, and general
(over)plot commands for text, line, symbols, etc.;
<LI>main plot commands <A NAME="8097"> </A> which do the actual
plotting and overplotting of data (<I>i.e.</I> images, tables,
descriptors or keywords);
<LI>cursor commands <A NAME="8099"> </A> which use the graphics
cursor.
</UL>
<P>
Below, subsection <A HREF="node86.html#graphic-devices">6.1.2</A> first describes how graphic
display units (<I>e.g.</I> terminals, workstations) can be activated inside
the MIDAS environment.
Thereafter, in the subsections <A HREF="node87.html#general-commands">6.1.3</A>
to <A HREF="node94.html#graphic-cursor-commands">6.1.5</A> the plot commands available in MIDAS
will be discussed. In subsection <A HREF="node95.html#handling-of-plotfiles">6.1.6</A> information
can be found about how plot files can be manipulated.
In section <A HREF="node97.html#examples">6.1.8</A> a number of examples are presented to
illustrate the available commands and their syntax. Finally, in
subsection <A HREF="node98.html#plot-command-summary">6.1.9</A> an overview is given of all
the available graphic commands in MIDAS.
<P>
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<ADDRESS>
<I>Petra Nass</I>
<BR><I>1999-06-09</I>
</ADDRESS>
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