# Identify the significant axis using the Kaiser-Guttman criterion
ev <- spe.h.pca$CA$eig
ev[ev>mean(ev)]
n <- length(ev)
barplot(ev, main="Eigenvalues", col="grey", las=2)
abline(h=mean(ev), col="red") 
legend("topright", "Average eigenvalue", lwd=1, col=2, bty="n")