Rasterize a Habitat Object — habitat

Converts a spatial habitat object into a terra::SpatRaster. The resulting raster stores the weight values of the habitat geometries. Areas explicitly defined as non-habitat (habitat = FALSE) are assigned NA.

Usage

habitat_raster(ground_raster, habitat)

Arguments

ground_raster: A terra::SpatRaster object used as a reference template. It provides the extent, resolution, and coordinate reference system (CRS).
habitat: A habitat object (inheriting from sf).

Value

A terra::SpatRaster containing habitat weights, with NA values in explicit non-habitat zones.

Details

The function maps the continuous or categorical weights of the habitat geometries onto a raster grid.

Background handling: By default, pixels not covered by any geometry are assigned a weight of 0 and are considered passable (habitat = TRUE).

Exclusion zones: Geometries added via add_nohabitat() act as absolute barriers. Any pixel intersecting these geometries will be assigned NA, overriding any underlying weight. If overlapping polygons exist, the order of features in the habitat object determines the final value (last on top).

Examples

if (FALSE) { # \dontrun{
library(terra)
library(sf)

# Create a dummy reference raster
ref_grid <- rast(nrows=10, ncols=10, xmin=0, xmax=10, ymin=0, ymax=10)

# Create habitat zones
good_hab <- st_sf(geometry = st_sfc(st_polygon(list(cbind(c(1, 9, 9, 1, 1), c(1, 1, 9, 9, 1))))))
bad_hab  <- st_sf(geometry = st_sfc(st_polygon(list(cbind(c(4, 6, 6, 4, 4), c(4, 4, 6, 6, 4))))))

# Build habitat object
my_habitat <- habitat() |>
  add_habitat(good_hab, weight = 0.8) |>
  add_nohabitat(bad_hab)

# Rasterize
hab_rast <- habitat_raster(ref_grid, my_habitat)
plot(hab_rast)
} # }