I have used the function
plotPCA(vsd, intgroup = c("location", "station"))
to visualize a PCA with all my samples (genes expressed differently on different samples, under different environmental conditions).
I would like to plot the environmental variables (conditions of the samples) with arrow on top to see the effect of the environmental variables. similar to what they do in "facto extra" -> fvizpcabiplot. Or is there a way to merge the PCA I have created adding the environmental variables on top?