plot.funData function

Plotting univariate functional data

This function plots observations of univariate functional data on their domain.

## S3 method for class 'funData'
plot(
  x,
  y,
  obs = seq_len(nObs(x)),
  type = "l",
  lty = 1,
  lwd = 1,
  col = NULL,
  xlab = "argvals",
  ylab = "",
  legend = TRUE,
  plotNA = FALSE,
  add = FALSE,
  ...
)

## S4 method for signature 'funData,missing'
plot(x, y, ...)

Arguments

• x: An object of class funData.

• y: Missing.

• obs: A vector of numerics giving the observations to plot. Defaults to all observations in x. For two-dimensional functions (images) obs must have length 1.

• type: The type of plot. Defaults to "l" (line plot). See plot for details.

• lty: The line type. Defaults to 1 (solid line). See par for details.

• lwd: The line width. Defaults to 1. See par for details.

• col: The color of the functions. If not supplied (NULL, default value), one-dimensional functions are plotted in the rainbow palette and two-dimensional functions are plotted using tim.colors from package fields-package.

• xlab, ylab: The titles for x- and y-axis. Defaults to "argvals"

  for the x-axis and no title for the y-axis. See plot for details.

• legend: Logical. If TRUE, a color legend is plotted for two-dimensional functions (images). Defaults to TRUE.

• plotNA: Logical. If TRUE, missing values are interpolated using the approxNA function (only for one-dimensional functions). Defaults to FALSE.

• add: Logical. If TRUE, add to current plot (only for one-dimensional functions). Defaults to FALSE.

• ...: Additional arguments to matplot

  (one-dimensional functions) or image.plot/ image (two-dimensional functions).

Details

If some observations contain missing values (coded via NA), the functions can be interpolated using the option plotNA = TRUE. This option relies on the na.approx function in package zoo and is currently implemented for one-dimensional functions only in the function approxNA.

Warning

The function is currently implemented only for functional data with one- and two-dimensional domains.

Examples

oldpar <- par(no.readonly = TRUE)

# One-dimensional
argvals <- seq(0,2*pi,0.01)
object <- funData(argvals,
                   outer(seq(0.75, 1.25, length.out = 11), sin(argvals)))

plot(object, main = "One-dimensional functional data")

# Two-dimensional
X <- array(0, dim = c(2, length(argvals), length(argvals)))
X[1,,] <- outer(argvals, argvals, function(x,y){sin((x-pi)^2 + (y-pi)^2)})
X[2,,] <- outer(argvals, argvals, function(x,y){sin(2*x*pi) * cos(2*y*pi)})
object2D <- funData(list(argvals, argvals), X)

plot(object2D, main = "Two-dimensional functional data (obs 1)", obs = 1)
plot(object2D, main = "Two-dimensional functional data (obs 2)", obs = 2)
## Not run: plot(object2D, main = "Two-dimensional functional data")
 # must specify obs!

### More examples ###
par(mfrow = c(1,1))

# using plotNA
if(requireNamespace("zoo", quietly = TRUE))
{
objectMissing <- funData(1:5, rbind(c(1, NA, 5, 4, 3), c(10, 9, NA, NA, 6)))
par(mfrow = c(1,2))
plot(objectMissing, type = "b", pch = 20, main = "plotNA = FALSE") # the default
plot(objectMissing, type = "b", pch = 20, plotNA = TRUE, main = "plotNA = TRUE") # requires zoo
}

# Changing colors
plot(object, main = "1D functional data in grey", col = "grey")
plot(object, main = "1D functional data in heat.colors", col = heat.colors(nObs(object)))

plot(object2D, main = "2D functional data in topo.colors", obs = 1, col = topo.colors(64))
par(oldpar)

See Also

funData, matplot, image.plot, image