base plots for tfs

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

Usage

# S3 method for class '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 class 'tf'
lines(x, arg, n_grid = 50, alpha = min(1, max(0.05, 2/length(x))), ...)

# S3 method for class 'tf'
points(
  x,
  arg,
  n_grid = NA,
  alpha = min(1, max(0.05, 2/length(x))),
  interpolate = FALSE,
  ...
)

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 (see grDevices::rgb()) for noodle transparency. Defaults to 2/(no. of observations). Lower is more transparent.

...

additional arguments for graphics::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.

Value

the plotted tf-object, invisibly.

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.

Examples

f <- tfd(sin(seq(0, 2 * pi, length.out = 51)), arg = seq(0, 1, length.out = 51))
plot(f)

plot(c(f, 2 * f), type = "lasagna")