New annotations are created by subtracting annotations from annotations on other tiers. This function can be started from Tier > Create Annotations from Subtraction…. This will open the Create Annotations From Subtraction window that is based on 4 steps.

1. Step 1/4: File and Tier Selection ( see Create annotations from overlaps)
2. Step 2/4: Subtract Computation Criteria

   In this step you can choose the subtraction computation criteria in the Subtract computation criteria window

   Figure 2.123. Subtract Computation Criteria

   

   You can choose one of the following:
   • Subtraction based on 'exclusive or' logic If this option is selected, the subtracts will be computed based on the 'Exclusive-or" logic.
   • Subtraction Selecting this option, will allow you to select a reference tier from which the annotations of the other selected tiers will be subtracted from.
   Click on the
   
   icon to know more about the differences between the above mentioned options.

3. Step 3/4: Destination Tier Name Specification (see Destination Tier Name Specification)
4. Step 4/4: Destination Tier Value Specification

   Here you can specify the value for the destination tier.

   Figure 2.124. Destination Tier Value Specification

   

   For detailed explanation on the options see Destination Tier Value Specification.

   Finally, you can click on Finish. The new tier will be created and populated.