This layer add lines representing a single or a group of parametric or smooth 1D effects.
l_fitLine(...)An object of class gamLayer.
graphical arguments to be passed to ggplot2::geom_line.
When used in conjuction with plot.fs.interaction.1D, which plots smooth effects
of type bs="fs", this function uses transparency to avoid over-plotting.
This can be avoided by setting alpha = 1 in the call to l_fitLine.
See plot.mgcv.smooth.1D, plot.ptermNumeric, or plot.fs.interaction.1D for examples.