# Adds a threshold constraint to a scenario object

Source:`R/add_constraint.R`

`add_constraint_threshold.Rd`

This option adds a `threshold()`

constraint to a scenario projection,
thus effectively applying the threshold as mask to each projection step made
during the scenario projection.

Applying this constraint thus means that the `"suitability"`

projection is
clipped to the threshold. This method requires
the `threshold()`

set for a scenario object.

It could be in theory possible to re calculate the threshold for each time step based on supplied parameters or even observation records. So far this option has not been necessary to implement.

## Usage

```
add_constraint_threshold(mod, updatevalue = NA, ...)
# S4 method for BiodiversityScenario
add_constraint_threshold(mod, updatevalue = NA, ...)
```

## Arguments

- mod
A

`BiodiversityScenario`

object with specified predictors.- updatevalue
A

`numeric`

indicating to what the masked out values (those outside) the threshold should become (Default:`NA`

).- ...
passed on parameters. See also the specific methods for adding constraints.

## See also

Other constraint:
`add_constraint()`

,
`add_constraint_MigClim()`

,
`add_constraint_adaptability()`

,
`add_constraint_boundary()`

,
`add_constraint_connectivity()`

,
`add_constraint_dispersal()`

,
`add_constraint_minsize()`

,
`simulate_population_steps()`