# NOT RUN {
 # pixel image
 v <- as.im(function(x,y){factor(round(5 * (x^2 + y^2)))}, W=owin())
 levels(v) <- letters[seq(length(levels(v)))]
 as.tess(v)
 # quadrat counts
 data(nztrees)
 qNZ <- quadratcount(nztrees, nx=4, ny=3)
 as.tess(qNZ)
# }
Run the code above in your browser using DataLab