# NOT RUN {
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=FALSE)
plot(arr)
# }
# NOT RUN {
## manually try to find new places for the labels: each arrow is marked
## active in turn, use the left mouse button to find a better location
## for the label. Use the right mouse button to go on to the next
## variable.
arr1 <- placeLabels(arr)
## now do the plot again:
plot(predict(milk.pca)[,c(2,3)])
plot(arr1)
# }
# NOT RUN {
# }
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