r <- raster(ncols=10, nrows=10)
r[] <- runif(ncell(r)) * 1:ncell(r)
z <- r
z[] <- rep(1:5, each=20)
zonal(r, z, 'mean')
zonal(r, z, 'min')
zonal(r, z, 'sum')
# using a function, rather than a character value
zonal(r, z, sum)
Run the code above in your browser using DataLab