set_min_nb_pus_objective {restoptr}

Set an objective to minimize the number of planning units

Description

Specify that a restoration problem (restopt_problem()) should minimize the number of planning units.

Usage

set_min_nb_pus_objective(problem)

Arguments

problem

restopt_problem() Restoration problem object.

Details

Planning units correspond to aggregated cells from the original dataset. Minimizing the number of planning units reduces the spatial extent of the restoration area.

Value

An updated restoration problem (restopt_problem()) object.

See Also

Other objectives: set_max_iic_objective(), set_max_mesh_objective(), set_max_nb_pus_objective(), set_max_restore_objective(), set_min_restore_objective(), set_no_objective()

Examples

# load data
habitat_data <- rast(
  system.file("extdata", "habitat_hi_res.tif", package = "restoptr")
)

locked_out_data <- rast(
 system.file("extdata", "locked_out.tif", package = "restoptr")
)

# plot data
plot(rast(list(habitat_data, locked_out_data)), nc = 2)

# create problem with locked out constraints
p <- restopt_problem(
    existing_habitat = habitat_data,
    aggregation_factor = 16,
    habitat_threshold = 0.7
  ) %>%
  set_min_nb_pus_objective() %>%
  add_restorable_constraint(
    min_restore = 5,
    max_restore = 5,
  ) %>%
  add_locked_out_constraint(data = locked_out_data) %>%
  add_settings(time_limit = 1)

# print problem
print(p)

# solve problem
s <- solve(p)

# plot solution
plot(s)