Add a semi-continuous decision to a conservation planning problem(). This is a relaxed decision where a part of a planning unit can be prioritized, as opposed to the entire planning unit, which is the default function (see add_binary_decisions()). This decision is similar to the add_proportion_decisions() function except that it has an upper bound parameter. By default, the decision can range from prioritizing none (0%) to all (100%) of a planning unit. However, an upper bound can be specified to ensure that at most only a fraction (e.g. 80%) of a planning unit can be preserved. This type of decision may be useful when it is not practical to conserve entire planning units.

add_semicontinuous_decisions(x, upper_limit)

Arguments

x

problem() (i.e. ConservationProblem) object.

upper_limit

numeric value specifying the maximum proportion of a planning unit that can be reserved (e.g. set to 0.8 for 80%).

Value

Object (i.e. ConservationProblem) with the decisions added to it.

Details

Conservation planning problems involve making decisions on planning units. These decisions are then associated with actions (e.g. turning a planning unit into a protected area). If no decision is explicitly added to a problem, then the binary decision class will be used by default. Only a single decision should be added to a ConservationProblem object. Note that if multiple decisions are added to a problem object, then the last one to be added will be used.

See also

Examples

# set seed for reproducibility set.seed(500) # load data data(sim_pu_raster, sim_features, sim_pu_zones_stack, sim_features_zones) # create minimal problem with semi-continuous decisions p1 <- problem(sim_pu_raster, sim_features) %>% add_min_set_objective() %>% add_relative_targets(0.1) %>% add_semicontinuous_decisions(0.5) %>% add_default_solver(verbose = FALSE) # \dontrun{ # solve problem s1 <- solve(p1) # plot solutions plot(s1, main = "solution")
# } # build multi-zone conservation problem with semi-continuous decisions p2 <- problem(sim_pu_zones_stack, sim_features_zones) %>% add_min_set_objective() %>% add_relative_targets(matrix(runif(15, 0.1, 0.2), nrow = 5, ncol = 3)) %>% add_semicontinuous_decisions(0.5) %>% add_default_solver(verbose = FALSE) # \dontrun{ # solve the problem s2 <- solve(p2) # print solution print(s2)
#> class : RasterStack #> dimensions : 10, 10, 100, 3 (nrow, ncol, ncell, nlayers) #> resolution : 0.1, 0.1 (x, y) #> extent : 0, 1, 0, 1 (xmin, xmax, ymin, ymax) #> crs : NA #> names : zone_1, zone_2, zone_3 #> min values : 0, 0, 0 #> max values : 0.5, 0.5, 0.5 #>
# plot solution # panels show the proportion of each planning unit allocated to each zone plot(s2, axes = FALSE, box = FALSE)
# }