Hi,
It is easier with the panel.number function. Following the example proposed
by Tim:
library(rasterVis)
f <- system.file("external/test.grd", package="raster")
r <- raster(f)
s <- stack(r, r+500, r-500)
labs <- c("a.", "b.", "c.")
levelplot(s) + layer(grid.text(labs[panel.number()], .95, .1))
Best,
Oscar.
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Oscar Perpi??n Lamigueiro
Dpto. Ing. El?ctrica, Electr?nica, Autom?tica y F?sica Aplicada (ETSIDI-UPM)
Grupo de Sistemas Fotovoltaicos (IES-UPM)
URL: http://oscarperpinan.github.io