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. Coordinates with group NA are omitted.
groupFun
Function used to aggregate the projected coordinates
if group is specified.
plot
Logical,if TRUE the axes are added to the current plot.
...
Passed to arrows.
Value
projAxes invisibly returns an object of class
"projAxes", which can be
added to an existing plot by its 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=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)
## End(Not run)