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Recruitment
Recruitment Rules populate a community in its smallest size class in elements that meet a specified condition. Recruitment rules are configured per community, which is unique. Most rules are configured per community-class. Multiple recruitment rules may be created for a single community.
Recruitment Rules tab
The Recruitment Rules tab allows you to define the conditions required for recruitment such that an element in the study area that meets those condition is populated with new recruits that begin at the lower limit of the lowest size class for the community (Figure).
Figure. The Recruitment Rules interface.
Rule Name: displays name of selected recruitment rule as part of dropdown list of all recruitment rules in the study.
Add, Rename, Copy, and Delete Rule: described above in the common features section.
Community: dropdown list of all communities in the study.
Season: start and end of season for the recruitment rule.
Recruit in elements already inhabited by this community: this checkbox controls whether elements already recruited by a community are further recruited by the community until the end of the recruitment rule’s season. When checked, recruitment will only occur in elements that do not have any community members of its lowest size class.
Data/Variables: Feature Classes: table where conditions for recruitment are configured using feature class data/variables.
Data/Variables: Rasters: table where conditions for recruitment are configured using raster data/variables.
Expression Builder: field contains the expression that guides how feature class and raster conditions need to be met to trigger recruitment.
Apply: clicking this button saves the recruitment rule.
Data/Variables
With a recruitment rule, a community recruits during the recruitment season and when an expression that typically contains one or more conditions is met. Conditions for recruitment are configured in the Data/Variables: Feature Classes and Data/Variables: Rasters tables.
These conditions can then be used as variables in the Expression Builder. A recruitment rule can have multiple variables configured in these tables, and a recruitment rule can use a combination of feature classes and rasters. Each recruitment rule variable must have a unique name.
Rows can be added and deleted from these tables using the – and + buttons.
Feature Classes
When a condition for recruiting elements in the study area depends on string values in a feature data set, the corresponding recruitment variable is configured in the Data/Variables: Feature Classes table.
The list of available variables contains the feature datasets created in the Data workspace. The selected variable must contain strings. In the Data_and_variables.h5 file, the selected variable must have a datastrings table.
The conditional operators in the Data/Variables: Feature Classes table are limited to “=” and “!=”. Feature classes determine whether a string exists or does not exist in the reference variable per element.
The string used for validating the condition is entered directly in the last field of a recruitment rule variable row in the Data/Variables:Feature Classes. The string is entered directly without the need for quotation marks.
If the selected variable used does not have strings, the condition returns as false.
Rasters
When a condition for recruiting elements in the study area is dependent on numeric values in a raster data set, the corresponding recruitment variable is configured in the Data/Variables: Rasters table.
The list of available variables includes any data or variable created in the study. Selecting the desired data or variable is done through the Variable Picker accessed from the ellipses button when configuring a recruitment rule variable in the Data/Variables: Rasters table.
The available conditional operators in the Data/Variables: Rasters are “<”, “<=”, “=”, “>”, and “>=”. By default, “=” is selected.
In the right-most field for a row, the value needed for the condition is entered.
Expression Builder
In the Expression Builder, variables for the recruitment rule that were configured in the Data/Variables tables are defined to create a Boolean expression. When variables are defined in the Expression Builder, a “$” symbol is prepended to the name of the variable. For example, a variable created in the Data/Variables: Feature Classes is named “recruitment_factor”. In the Expression Builder, this is entered as “$recruitment_factor”.
Multiple recruitment rule variables can be added to the Expression Builder. These are concatenated using “and” or “&&” for an AND expression, and “or” or “||” for an OR expression. Using “AND” or “OR” produces an error in expression.
The Expression Builder can only use the variables created in the Data/Variables: Feature Classes and Data/Variables: Rasters tables. For example, using a model variable cannot be defined in the Expression builder. This must be added as a variable within the recruitment rule first.
Configuring a Recruitment rule
When creating a recruitment rule, you must:
- Assign a unique rule name,
- Select the community to configure recruitment rule for,
- Configure the season for the recruitment,
- Configure whether or not to recruit in elements already inhabited by the community
- Configure the recruitment rule variables, and
- Configure the Boolean expression for the recruitment rule.
Creating a New Rule Name
The first step in creating a new recruitment rule is to assign a rule name. Because multiple recruitment rules may be created in a study and for the same community, each recruitment rule must have a unique name. When attempting to create a recruitment rule that duplicates an existing rule’s name, an error is produced.
To create a new recruitment rule:
- Click the Add Rule This loads the New Rule dialog (Figure).
- Enter a unique rule name for the new recruitment rule in the New Rule
- Click OK in the New Rule
- After the New Rule dialog closes, the new rule name is displayed in the Rule Name
Figure. Interface for creating a new recruitment rule.
Select Community
When creating a recruitment rule, the community and size class is selected from the Community dropdown.
To select the Community:
- Expand the Community drop down. The drop down lists all the available communities in the study.
Set Season
The recruitment rule takes effect for a season. This uses the day and month in the format of <ddMmm>. For example, January 5th is entered as “05Jan”. This is configured by either directly entering the date or by using the calendar tool accessed from the – button next to a date field.
To configure the season:
- Enter date for start of season.
- Enter date for end of season.
Set Whether to Recruit in Elements Already Inhabited by the Community
By default, the Recruit in elements already inhabited by this community is unchecked. With the checkbox unchecked, the recruitment rule stops once an element is inhabited by the community.
When an element is already recruited by a community and the Recruit in elements already inhabited by this community is checked, the recruitment in the element continues until the end of the season for the recruitment rule.
Set Recruitment Rule Variables
For a recruitment rule variable, determine the data or variable to use for determining the condition to meet for the community to recruit in the element. Depending on the data and variable, the recruitment rule variable may be created in either the Feature Classes table or the Rasters table.
To configure a recruitment rule variable:
- Determine the data or variable to use as reference for recruiting elements in the study area.
- Determine whether the recruitment rule variable is a Feature Class or a Raster.
- Assign a name for the recruitment rule variable.
- Select the reference data or variable.
- Select the conditional operator.
- Enter the value required for the condition.
Configure Boolean Expression
To configure the Boolean expression for the recruitment rule:
- Prepend the recruitment rule variable name(s) with a “$”.
- If there are multiple variables, concatenate these to form the Boolean Expression.
- Click the Apply button (Figure).
Figure. Click the Apply button to save the recruitment rule.
Simulation
When a recruitment rule occurs, the community assigned to the recruitment rule populates the elements that meet the Boolean expression configured for the rule.
Recruitment occurs at the end of the period for the simulation time step. For example, given a daily simulation, the recruitment occurs at 24:00 of a given day.
With successfully recruiting elements in the study area, these elements reflect the density and size of the recruited community. The recruitment rule also stops once the element is populated with the community at its smallest size class unless the Recruit in elements already inhabited by this community is checked.
Recruiting in elements already inhabited
By default, a recruitment rule will have the Recruit in elements already inhabited by this community unchecked. When unchecked, recruitment will not occur in elements already populated with the community (any size class).
Recruitment in elements already inhabited will only occur when the Recruit in elements already inhabited by this community is checked and the element is not populated by the community at its smallest size class. If the elements to recruit are already populated by the community at its smallest size class, recruitment still does not occur even with the checkbox checked. The recruitment continues until the end of the rule’s season.
Recruiting in elements with multiple rules
Because there can be multiple recruitment rules for a community, the rules execute separately when the seasons and the elements do not overlap. If for the same season, multiple recruitment rules occur and populate separate elements, each recruitment rule takes effect.
When multiple rules are occurring for the same season and into the same elements, all the recruitment rules take effect until one is successful. The remaining recruitment rules fail once the elements are occupied.
Simulation Output
After a simulation is computed with recruitment rules, results can be observed during animation in the Simulation Map. When recruitment rules successfully occur for a simulation, this can be observed in the density and size values in an element. There are also tables related to recruitment rules that are generated in the results Simulation HDF tables.
When a simulation with recruitment rules successfully occurs, the Simulation HDF File has tables for the Recruitment Action Table, Density, and Size.
The Simulation Map displays the values from the action table of recruitment rules in a simulation.
Each recruitment rule created for a study is assigned a unique Rule ID.
Under the Action Table at the community level, the action table for Recruitment is generated. The Recruitment Action Table notes when a recruitment rule occurs. Each recruitment rule is noted with its unique Rule ID.
Configuring Spatial Output Controls
The Spatial Output Controls, which are accessed from the Project Properties dialog, control whether additional tables are generated in the simulation HDF file after computing a simulation with configured road rules.
The Spatial Output Controls have checkboxes for Recruitment under the Rules section. When this checkbox is checked, the action table for recruitment rules is generated in the Simulation HDF file. By default, the Recruitment checkbox is checked.
Configuring the Animation Properties
In the Animation Properties, a simulation with a computed recruitment rule will have options to display the recruitment rule action table and the resulting density and size from successful recruitment in a simulation.
- Recruitment Rule: When this option is selected, the values from the recruitment action table is animated in the Simulation Map.
- Size: When this option is selected, the size of the community is displayed on the Simulation Map.
- Density: When this option is selected, the density of the community is displayed on the Simulation Map.
Animating the Recruitment Rule
To animate the values from the Action Table of recruitment rules on the Simulation Map, in the Animation Properties:
- Select the Community to animate on the Simulation Map.
- Select the Model Variable radio button.
- Select Recruitment Rule in the corresponding dropdown.
- Configure the Tic Interval and Contour Limits as needed.
- Click the Apply
To animate the recruitment occurring by observing the Density values of the community in the Simulation Map, in the Animation Properties:
- Select the Community to animate on the Simulation Map.
- Select the Model Variable radio button.
- Select the Density in the corresponding dropdown.
- Configure the Tic Interval and Contour Limits as needed.
- Click the Apply
To animate the recruitment occurring by observing the Size values of the community in the Simulation Map, in the Animation Properties:
- Select the Community to animate on the Simulation Map.
- Select the Model Variable radio button.
- Select the Size in the corresponding dropdown.
- Configure the Tic Interval and Contour Limits as needed.
- Click the Apply