Prepare an SWD object

Given the coordinates, the species' name and the environmental variables, the function creates an SWD object (sample with data).

prepareSWD(species, env, p = NULL, a = NULL, categorical = NULL)

Arguments

species	character. The name of the species.
env	stack containing the environmental variables used to extract the values at coordinate locations.
p	data.frame. The coordinates of the presence locations.
a	data.frame. The coordinates of the absence/background locations.
categorical	vector indicating which of the environmental variable are categorical, default is NULL.

Value

An SWD object.

Details

The SWD object is created in a way that the presence locations are always before than the absence/background locations.

Author

Sergio Vignali

Examples

# Acquire environmental variables
files <- list.files(path = file.path(system.file(package = "dismo"), "ex"),
                    pattern = "grd", full.names = TRUE)
predictors <- raster::stack(files)

# Prepare presence and background locations
p_coords <- virtualSp$presence
bg_coords <- virtualSp$background

# Create the SWD object
data <- prepareSWD(species = "Virtual species", p = p_coords, a = bg_coords,
                   env = predictors, categorical = "biome")
#> Extracting predictor information for presence locations...
#> Extracting predictor information for absence/background locations...
data
#> Object of class SWD 
#> 
#> Species: Virtual species 
#> Presence locations: 400 
#> Absence locations: 5000 
#> 
#> Variables:
#> ---------
#> Continuous: bio1 bio12 bio16 bio17 bio5 bio6 bio7 bio8 
#> Categorical: biome