plot.tf: `base` plots for `tf`s

Description

Some base functions for displaying functional data in spaghetti- (i.e., line plots) and lasagna- (i.e., heat map) flavors.

Usage

# S3 method for tf
plot(
  x,
  y,
  n_grid = 50,
  points = is_irreg(x),
  type = c("spaghetti", "lasagna"),
  alpha = min(1, max(0.05, 2/length(x))),
  ...
)
# S3 method for tf
lines(x, arg, n_grid = 50, alpha = min(1, max(0.05, 2/length(x))), ...)
# S3 method for tf
points(
  x,
  arg,
  n_grid = NA,
  alpha = min(1, max(0.05, 2/length(x))),
  interpolate = FALSE,
  ...
)

Value

the plotted tf-object, invisibly.

Arguments

x: an tf object
y: (optional) numeric vector to be used as arg (i.e., for the x-axis...!)
n_grid: minimal size of equidistant grid used for plotting, defaults to 50. See details.
points: should the original evaluation points be marked by points? Defaults to TRUE for irregular tfd and FALSE for all others
type: "spaghetti": line plots, "lasagna": heat maps.
alpha: alpha-value (seegrDevices::rgb()) for noodle transparency. Defaults to 2/(no. of observations). Lower is more transparent.
...: additional arguments for matplot() ("spaghetti") or image() ("lasagna")
arg: evaluation grid (vector)
interpolate: should functions be evaluated (i.e., inter-/extrapolated) for arg for which no original data is available? Only relevant for tfd, defaults to FALSE

Details

If no second argument y is given, evaluation points (arg) for the functions are given by the union of the tf's arg and an equidistant grid over its domain with n_grid points. If you want to only see the original data for tfd-objects without inter-/extrapolation, use n_grid < 1 or n_grid = NA.

References

Swihart, J B, Caffo, Brian, James, D B, Strand, Matthew, Schwartz, S B, Punjabi, M N (2010). “Lasagna plots: a saucy alternative to spaghetti plots.” Epidemiology (Cambridge, Mass.), 21(5), 621--625.