sdm_threshold: Thresholds a continuous relative occurrence rate raster to...

In bmaitner/pbsdm: Small Sample Size Species Distribution Modeling

Thresholds a continuous relative occurrence rate raster to create a binary raster.

Description

This function thresholds a continuous relative occurrence rate raster to produce a binary presence/absence raster.

Usage

sdm_threshold(
  prediction_raster,
  occurrence_sf,
  quantile = 0.05,
  return_binary = TRUE
)

Arguments

prediction_raster	Raster containing continuous predictions of relative occurrence rate to be thresholded.
occurrence_sf	An sf object containing presence locations. Should be in the projection of the prediction raster
quantile	Numeric between 0 and 1. Quantile to use for thresholding (defaults to 0.05). Set to 0 for minimum training presence.
return_binary	LOGICAL. Should the raster returned be binary (presence/absence)? If FALSE, predicted presences will retain their 'suitability" scores.

Value

A SpatRaster object containing a range map. Maps may be either binary or continuous, depending upon the return_binary argument.

Author(s)

Cecina Babich Morrow (modified by Brian Maitner)

Examples

{

# load in sample data

library(S4DM)
library(terra)

# occurrence points
  data("sample_points")
  occurrences <- sample_points

# environmental data
  env <- rast(system.file('ex/sample_env.tif', package="S4DM"))

# rescale the environmental data

  env <- scale(env)

 bg_data <- get_env_bg(coords = occurrences,
                       env = env,
                       method = "buffer",
                       width = 100000)

 pres_data <- get_env_pres(coords = occurrences,
                           env = env)

 pnp_model <-fit_plug_and_play(presence = pres_data$env,
                   background = bg_data$env,
                   method = "gaussian")

 pnp_continuous <- project_plug_and_play(pnp_model = pnp_model,
                                         data = bg_data$env)

 #Make an empty raster to populate
 out_raster <- env[[1]]
 values(out_raster) <- NA

 # use the bg_data for indexing
 out_raster[bg_data$bg_cells] <- pnp_continuous

 plot(out_raster)

 #convert to a binary raster

 out_raster_binary <-
   sdm_threshold(prediction_raster = out_raster,
               occurrence_sf = pres_data$occurrence_sf,
               quantile = 0.05,
               return_binary = TRUE)

 plot(out_raster_binary)

}

bmaitner/pbsdm documentation built on Feb. 8, 2025, 2:27 p.m.