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)
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 |
An SWD object.
The SWD object is created in a way that the presence locations are always before than the absence/background locations.
Sergio Vignali
# 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")#>#>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