View source: R/panel.ellipse.R
panel.ellipse | R Documentation |
A lattice panel function that computes and draws a confidence ellipsoid from bivariate data, possibly grouped by a third variable.
panel.ellipse(x, y, groups = NULL, level = 0.68, segments = 50, robust = FALSE, center.pch = 3, center.cex = 2, ..., type, pch, cex)
x, y |
Numeric vectors of same length giving the bivariate data. Non-numeric variables will be coerced to be numeric. |
groups |
Optional grouping variable. |
level |
Confidence level for the ellipse. |
segments |
Number of segments used to approximate the ellipse. |
robust |
Logical indicating whether a robust method should be used. If
|
center.pch |
Plotting character for the center (fitted mean). If |
center.cex |
Character expansion (size) multipler for the symbol indicating the center. |
... |
Further arguments, typically graphical parameters. Passed on to
|
type, pch, cex |
Parameters that are ignored; these are present only to make sure
they are not inadvertently passed on to |
Deepayan Sarkar, extending code contributed by Michael Friendly.
xyplot(Sepal.Length ~ Petal.Length, groups=Species, data = iris, scales = "free", par.settings = list(superpose.symbol = list(pch=c(15:17)), superpose.line = list(lwd=2, lty=1:3)), panel = function(x, y, ...) { panel.xyplot(x, y, ...) panel.ellipse(x, y, ...) }, auto.key = list(x = .1, y = .8, corner = c(0, 0))) ## Without groups xyplot(Sepal.Length ~ Petal.Length, data = iris, scales = "free", par.settings = list(plot.symbol = list(cex = 1.1, pch=16)), panel = function(x, y, ...) { panel.xyplot(x, y, ...) panel.ellipse(x, y, lwd = 2, ...) }, auto.key = list(x = .1, y = .8, corner = c(0, 0))) ## With conditioning xyplot(Sepal.Length ~ Petal.Length | Species, data = iris, scales = "free", par.settings = list(plot.symbol = list(cex = 1.1, pch=16)), layout=c(2,2), panel = function(x, y, ...) { panel.xyplot(x, y, ...) panel.ellipse(x, y, lwd = 2, ...) }, auto.key = list(x = .6, y = .8, corner = c(0, 0))) ## Compare classical with robust xyplot(Sepal.Length ~ Petal.Length | Species, data = iris, scales = "free", par.settings = list(plot.symbol = list(cex = 1.1, pch=16)), layout=c(2,2), panel = function(x, y, ...) { panel.xyplot(x, y, ...) panel.ellipse(x, y, lwd = 2, ...) panel.ellipse(x, y, lwd = 2, col="red", robust=TRUE, ...) })
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