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Generate simulated reefs

generate_reefs.Rd

Generate simulated reefs

Usage

generate_reefs(simulated_patch_sf, config_sp)

Arguments

simulated_patch_sf

A simulated patch as an sf object as generated by the function generate_patch

config_sp

A list that contains the parameters for filtering the field to patches. The list should contain the following parameters:

  • reef_width: a numeric representing the half the width of a ribbon representing the reef that is centered on the outline of the patch

Value

a list containing:

  • simulated_reefs_sf: a sfc multipolygon object that represents the simulated reefs

  • simulated_reefs_poly_sf: an sf object that represents the simulated reefs

Details

Generate simulated reefs from a simulated patches. A "reef" is a special type of patch that is created by buffering the outline of a patch to create a ribbon that is centered on the outline of the patch. The width of the ribbon is determined by the parameter reef_width. In this way, the resultin object more closely resembles a coral reef which tends to be an irregular ring or semi-ring shaped polygon with the coral growing mostly around the outside edge surrounding a central sandy lagoon.

Author

Murray

Examples

library(sf)
library(gstat)
library(ggplot2)
config_sp <- list(
 seed = 1,
 crs = 4326,
 model = "Exp",
 psill = 1,
 range = 15,
 nugget = 0,
 patch_threshold = 1.75,
 reef_width = 0.01
)
spatial_domain <- st_geometry(
  st_multipoint(
    x = rbind(
      c(0, -10),
      c(3, -10),
      c(10, -20),
      c(1, -21),
      c(2, -16),
      c(0, -10)
    )
  )
) |>
  st_set_crs(config_sp$crs) |>
  st_cast("POLYGON")
set.seed(config_sp$seed)
spatial_grid <- spatial_domain |>
  st_set_crs(NA) |>
  st_sample(size = 10000, type = "regular") |>
  st_set_crs(config_sp$crs)
simulated_field <- generate_field(spatial_grid, config_sp)
#> [using unconditional Gaussian simulation]
simulated_patches <- generate_patches(simulated_field, config_sp)
#> Spherical geometry (s2) switched off
#> Spherical geometry (s2) switched on
simulated_reefs <- generate_reefs(simulated_patches, config_sp)
#> Spherical geometry (s2) switched off
#> Spherical geometry (s2) switched on
ggplot() +
   geom_sf(data = simulated_reefs$simulated_reefs_sf, fill = "lightblue") +
   coord_sf(xlim = c(1.8, 2.3), ylim = c(-20.4, -19.9))