fortify.merMod(model, data = getData(model),
...)fortify is a function defined in the
ggplot2 package, q.v. for more details.
fortify is not defined here,
and fortify.merMod is defined as a function
rather than an S3 method, to avoid (1) inducing
a dependency on ggplot2 or (2) masking
methods from ggplot2.
This is currently an experimental feature.