Change raster panel titles using levelplot

Question

I'm using RasterVis and levelplot to make a trellis plot of some rasters. I am currently ok for most things but I would like to change the header for each panel from the filename to a chosen string (the filename is convoluted and long, i want to use just a year, for example '2004').

Looking at the levelplot page, it would indicate that levelplot goes looking for some settings as per the argument 'useRaster', either it goes to panel.levelplot or panel.levelplot.raster, but im struggling to use these latter functions.

Any help much appreciated, here's some sample code;

require(rasterVis)

layers <- c(1:4)
s2 <- stack()

for (i in layers) {
  r <- raster(nrows=100, ncols=100,ext)
  r[] <- sample(seq(from = 1, to = 6, by = 1), size = 10000, replace = TRUE)
  rasc <- ratify(r)
  rat <- levels(rasc)[[1]]
  rat$legend <- c("A","B","C","D","E","F")
  levels(rasc) <- rat
  s2 <- stack(s2, rasc)
}

levelplot(s2, col.regions=rev(terrain.colors(6)),main = "example")

In the above e.g., I would like "layer.1.1" to be "2004", and so on through to 2007

Sheaff

names argument of levelplot. What is ext object? – Caporetto

@ Pascal, sorry that was a raster extent i missed off the top of the code – Sheaff

Answer 1

require(rasterVis)

layers <- c(1:4)
s2 <- stack()

for (i in layers) {
  r <- raster(nrows=100, ncols=100)
  r[] <- sample(seq(from = 1, to = 6, by = 1), size = 10000, replace = TRUE)
  rasc <- ratify(r)
  rat <- levels(rasc)[[1]]
  rat$legend <- c("A","B","C","D","E","F")
  levels(rasc) <- rat
  s2 <- stack(s2, rasc)
}
levelplot(s2, col.regions=rev(terrain.colors(6)),main = "example", names.attr=2004:2007)

p.strip <- list(cex=1.5, lines=1, col="blue", fontfamily='Serif')

levelplot(s2, col.regions=rev(terrain.colors(6)), main = "example",
          names.attr=2004:2007, par.strip.text=p.strip)

Caporetto

is that it? just the names argument? but where is it on the help? can you adjust the font etc as well? – Sheaff

@Sheaff I wrote names, but strictly should be names.attr. In help page: Character, names to use in each panel. If missing its default value is the result of names(x) (after subsetting the layers to be displayed). – Caporetto