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Distance between the distribution of climate values for presences vs background

Source: R/dist_pres_vs_bg.R
dist_pres_vs_bg.Rd

For each environmental variable, this function computes the density functions of presences and absences and returns (1-overlap), which is a measure of the distance between the two distributions. Variables with a high distance are good candidates for SDMs, as species occurrences are confined to a subset of the available background.

Usage

dist_pres_vs_bg(.data, .col)

Arguments

.data

a data.frame (or derived object, such as tibble, or sf) with values for the bioclimate variables for presences and background

.col

the column containing the presences; it assumes presences to be the first level of this factor

Value

a name vector of distances

Examples

# This should be updated to use a dataset from tidysdm
data("bradypus", package = "maxnet")
bradypus_tb <- tibble::as_tibble(bradypus) %>%
  dplyr::mutate(presence = relevel(
    factor(
      dplyr::case_match(presence, 1 ~ "presence", 0 ~ "absence")
    ),
    ref = "presence"
  )) %>%
  select(-ecoreg)

bradypus_tb %>% dist_pres_vs_bg(presence)
#> pre6190_l10 frs6190_ann tmn6190_ann pre6190_ann vap6190_ann  pre6190_l7 
#>   0.4366602   0.4299480   0.4295013   0.4096230   0.3945855   0.3933454 
#>       h_dem tmp6190_ann dtr6190_ann  pre6190_l4 tmx6190_ann cld6190_ann 
#>   0.3647375   0.3316686   0.3288771   0.2544976   0.2418274   0.1812527 
#>  pre6190_l1 
#>   0.1297035