t of class mfd.</p></dd>


<dt>mapping</dt>
<dd><p>Set of aesthetic mappings additional
to <code>x</code> and <code>y</code> as passed to the function
<code>ggplot2::geom:line</code>.</p></dd>


<dt>data</dt>
<dd><p>A <code>data.frame</code> providing columns
to create additional aesthetic mappings.
It must contain a factor column "id" with the replication values
as in <code>mfdobj$fdnames[[2]]</code>.
If it contains a column "var", this must contain
the functional variables as in <code>mfdobj$fdnames[[3]]<