rainbow (version 1.6)

fboxplot: Functional bagplot and functional HDR boxplot

Description

Compute bivariate bagplot, functional bagplot and bivariate HDR boxplot, functional HDR boxplot.

Usage

fboxplot(data, plot.type = c("functional", "bivariate"),type = c("bag",
 "hdr"), alpha = c(0.01, 0.5), factor = 2.57, na.rm = TRUE, 
  xlab = data$xname, ylab = data$yname, ...)

Arguments

data

An object of class fds or fts.

plot.type

Version of boxplot. When plot.type="functional", a functional plot is provided. When plot.type="bivariate", a square bivariate plot is provided.

type

Type of boxplot. When type="bag", a bagplot is provided. When type="hdr", a HDR boxplot is provided.

alpha

Coverage probability for the functional HDR boxplot. $\alpha$ are the coverage percentages of the outliers and the central region.

factor

When type="bag", the outer region of a bagplot is the convex hull obtained by inflating the inner region by the bagplot factor.

na.rm

Remove missing values.

xlab

A title for the x axis.

ylab

A title for the y axis.

...

Other arguments.

Value

• Function produces a plot.

Details

The functional curves are first projected into a finite dimensional subspace. For simiplicity, we choose the subspace as $R^2$. Based on Tukey (1974)'s halfspace bagplot and Hyndman (1996)'s HDR boxplot, we order each data point in $R^2$ by data depth and data density. Outliers are those that have either lowest depth or lowest density.

References

J. W. Tukey (1974) "Mathematics and the picturing of data", Proceedings of the International Congress of Mathematicians, 2, 523-532, Canadian Mathematical Congress, Montreal. P. Rousseeuw, I. Ruts and J. Tukey (1999) "The bagplot: A bivariate boxplot", The American Statistician, 53(4), 382-387. R. J. Hyndman (1996) "Computing and graphing highest density regions", The American Statistician, 50(2), 120-126. R. J. Hyndman and H. L. Shang. (2009) "Rainbow plots, bagplots, and boxplots for functional data", Journal of Computational and Graphical Statistics, in press.

See Also

SVDplot

Examples

fboxplot(data = ElNino, plot.type = "functional", type = "bag")
fboxplot(data = ElNino, plot.type = "bivariate", type = "bag")
fboxplot(data = ElNino, plot.type = "functional", type = "hdr", alpha = c(0.07,0.5))
fboxplot(data = ElNino, plot.type = "bivariate", type = "hdr", alpha = c(0.07,0.5))