Calculate the difference between predictions of species presence for a baseline and scenario landscape

Usage

calc_change_SDM(
  pathin,
  SDM,
  baseline_name,
  scenario_name,
  pathout,
  overwrite = FALSE,
  differentiate = TRUE
)

Arguments

pathin, SDM: Character strings defining the filepath (pathin/SDM) containing the predicted probability of presence resulting from each distribution model, such as those created from running fit_SDM() and transform_SDM(); SDM must be one of "riparian", "waterbird_fall", or "waterbird_win".
baseline_name: Character string defining the filepath (pathin/SDM/baseline_name) containing the predictions for a baseline landscape
scenario_name: Character string defining the filepath (pathin/SDM/scenario_name) containing the predictions for a scenario landscape
pathout: Character string defining the filepath (pathout/SDM/scenario_name) where the results will be written
overwrite: Logical; passed to terra::writeRaster(); default FALSE
differentiate: Logical; if TRUE, locations where the predicted value is zero in both landscapes will be converted to NA

Value

Nothing; all output written to pathout/SDM/scenario_name

Details

This function is designed to handle predictions for multiple species provided as rasters in the baseline and scenario directories, matched by name. The difference is calculated as the predicted value for the scenario minus the predicted value for the baseline, such that positive values in the result represent an increased probability of presence, and negative values represent a reduced probability of presence.

If differentiate = TRUE, the function is also designed to distinguish between two types of zero values in the result: locations where the predicted value is the same in both landscapes (which will retain a value of zero difference), and locations where the predicted value is zero in both landscapes (which will be converted to NA).

Examples

# See vignette