entropy: Shannon entropy index on time at depth proportions
In SESman/rbl: Biologging tools for diving predators in R

Shannon entropy index on time at depth proportions

1	entropy(x, base = 2, scale = FALSE)

`x`	a character vector naming the depth layers.
`base`	base argument passed to `log`.
`scale`	if TRUE the output is divided by the `log(N)` where N is the number of layers so that outpout lies between 0 and 1.`log(N)` is the minimum entropy for sample with N layers where each observation of sample is unique i.e all probability are equal.

data(exses)
ind(exses)

brks <- do.call(seq, as.list(c(range(exses$tdr$depth, na.rm = TRUE), by = 2)))
exses$tdr$depth_cat <- as.character(cut(exses$tdr$depth, brks))
plot(tdrply(entropy, "depth_cat", ty = "!_/"), exses$stat$pca)