How to convert a "ppp" object to multitype object?

Question

How can you convert a "ppp" object to multitype object in order to run a cross k Kcross function in r?

Answer 1

You have to assign factor levels as marks to obtain multitype point patterns in spatstat:

library(spatstat)
baa <- ppp(x = 1, y = 1, window = square(10))
is.multitype(baa)
[1] FALSE
marks(baa) <- "gaa"
is.multitype(baa)
[1] FALSE
marks(baa) <- factor("gaa")
is.multitype(baa)
[1] TRUE

Then you can run Kcross function:

moo <- ppp(x = c(1,2), y = c(2,1), window = square(5), marks = factor(c("baa", "gaa")))
Kcross(moo)