projAxes {flexclust}R Documentation

Add Arrows for Projeted Axes to a Plot

Description

Adds arrows for original coordinate axes to a projection plot. Currently only a method for the results of prcomp exists.

Usage

projAxes(object, which=1:2, center=NULL,
                     col="red", radius=NULL,
                     minradius=0.1, textargs=list(col=col),
                     col.names=getColnames(object),
                     which.names="", group = NULL, groupFun = colMeans,
                     ...)

placeLabels(object)
## S4 method for signature 'projAxes':
placeLabels(object)

Arguments

object Return value of a projection method like prcomp.
which Index number of dimensions of (projected) input space that have been plotted.
center Center of the coordinate system to use in projected space. Default is the center of the plotting region.
col Color of arrows.
radius Relative size of the arrows.
minradius Minimum radius of arrows to include (relative to arrow size).
textargs List of arguments for text.
col.names Variable names of the original data.
which.names A regular expression which variable names to include in the plot.
group An optional grouping variable for the original coordinates.
groupFun Function used to aggregate the projected coordinates if group is specified.
... Passed to arrows.

Value

projAxes returns an object of class "projAxes", which is added to the current plot by its show and plot method.

Author(s)

Friedrich Leisch

Examples

data(milk)
milk.pca <- prcomp(milk, scale=TRUE)

## create a biplot step by step
plot(predict(milk.pca), type="n")
text(predict(milk.pca), rownames(milk), col="green", cex=0.8)
projAxes(milk.pca)

## the same, but arrows are blue, centered at origin and all arrows are
## plotted 
plot(predict(milk.pca), type="n")
text(predict(milk.pca), rownames(milk), col="green", cex=0.8)
projAxes(milk.pca, col="blue", center=0, minradius=0)

## use points instead of text, plot PC2 and PC3, manual radius
## specification, store result
plot(predict(milk.pca)[,c(2,3)])
arr <- projAxes(milk.pca, which=c(2,3), radius=1.2)
plot(arr)

[Package flexclust version 0.9-0 Index]