This function is a method of as.data.frame for a circular object.
# S3 method for circular
as.data.frame(x, row.names = NULL, optional = FALSE, ...)
object of class circular.
NULL or a character vector giving the row
    names for the data frame. Missing values are not allowed.
logical; if TRUE setting row names is
      optional.
additional arguments to be passed to or from methods.
Claudio Agostinelli