
<para>
    The text can include <termtext>symbolic fields</termtext>, placeholders
    for text that is automatically inserted when the legend is printed.
    For example, the field {ConciseGridDescription} is automatically
    replaced with a short description of the plot's <link
    target='#NMPlot_PrimaryGrid_id'>primary grid</link>.
</para>
<para>
    Symbolic fields can also represent graphical elements, such as
    a north arrow. Of particular interest is the {Plot} symbol, which
    represents the plot being annotated by the &TermForForm;. Each
    &TermForForm; should contain exactly one text cell that has the
    {Plot} symbol as part of its text.
</para>
<para>
    Some commonly used symbolic fields are:
</para>
<exhibit>
    <table>
        <tableheader>
            <tablecolumnheader horzjust='center'>
                Field
            </tablecolumnheader>
            <tablecolumnheader horzjust='left'>
                Description
            </tablecolumnheader>
        </tableheader>
        <tablerow>
            <tablecell>
                {ConciseGridDescription}
            </tablecell>
            <tablecell>
                Short description of the plot's primary grid
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {DetailedGridDescription}
            </tablecell>
            <tablecell>
                Longer, more detailed description of the plot's primary grid
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {Metric}
            </tablecell>
            <tablecell>
                The <link target='#NMPlot_GridDataMetric_id'>data metric</link>
                of the plot's primary grid: i.e., what is being measured by the
                grid. For example, "aircraft noise" or "water temperature"
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {Units}
            </tablecell>
            <tablecell>
                Physical units of the plot's primary grid. For example, "dB" or
                "degrees C".
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {GridFilename}
            </tablecell>
            <tablecell>
                Name of the file containing the plot's primary grid
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {CurrentDate}
            </tablecell>
            <tablecell>
                Date on which the plot is printed
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {CurrentTime}
            </tablecell>
            <tablecell>
                Time at which the plot is printed
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {Plot}
            </tablecell>
            <tablecell>
                The plot being printed
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {NorthArrow}
            </tablecell>
            <tablecell>
                An arrow indicating the direction of north on the plot
            </tablecell>
        </tablerow>
        <tablerow>
            <tablecell>
                {MapScale}
            </tablecell>
            <tablecell>
                A graphical distance bar showing the plot scale. You can change the
                units used by the graphical map scale: see <iref
                target='WCPUxWCF_ApplicationOptions_PhysicalUnits_id'/>.
            </tablecell>
        </tablerow>
    </table>
</exhibit>
