How to show matrix values on Levelplot

Question

I have a matrix data here, and I visualized it with levelplot. The Plot is placed below. But I just couldn\'t put the values into the plot, I mean I read this

Answer 1

Another option is to use layer() from latticeExtra. It allows you to overlay one plot on top of another, using the + operator familiar to ggplot2 enthusiasts:

library(latticeExtra)

## Applied to the example data in my other answer, this will produce
## an identical plot
levelplot(Z ~ X*Y, data = grid) +
layer(panel.text(X, Y, round(Z, 1)), data = grid)