fr2prob: Adjust probability of sampling based on frequency of...

In SESraster: Raster Randomization for Null Hypothesis Testing

Adjust probability of sampling based on frequency of occurrences.

Description

This function is used to adjust the probability of a species to be sampled across the raster, so that the sampled frequency of occurrence of the species is closer to the observed

Usage

fr2prob(x, rprob = NULL)

Arguments

x	SpatRaster. A presence-absence raster (stack).
rprob	SpatRaster. A raster (stack) of probabilities.

Value

numeric vector

Examples

library(SESraster)
library(terra)
# load random species distributions
r <- load_ext_data()

# applying the function
fr2prob(r)


f <- system.file("ex/elev.tif", package="terra")
r <- rast(f)
set.seed(510)
r10 <- rast(lapply(1:18,
                function(i, r, mn, mx){
                  app(r, function(x, t){
                    sapply(x, function(x, t){
                       x<max(t) & x>min(t)
                    }, t=t)
                  }, t=sample(seq(mn, mx), 2))
                }, r=r, mn=minmax(r)[1]+10, mx=minmax(r)[2]-10))

names(r10) <- paste("sp", 1:nlyr(r10))
fr2prob(r10)
# raw frequencies
unlist(terra::global(r10, function(x)sum(x, na.rm=TRUE)))

SESraster documentation built on Oct. 30, 2024, 9:16 a.m.