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Filtering annotations

It is often useful to view, use, or process some subset of the annotations that are in a Knowtator annotation project. We have created a simple mechanism for creating annotation filters for defining some subset of the annotations in a Knowtator project. For example, it may the case that you have part-of-speech tags created by one annotator and named entities created separately by three annotators. Filters can be used to view only named entities from one of the annotators or to run IAA metrics on two of the annotators.

A filter is defined as a set of conditions that an annotation must satisfy to not be "filtered out". There are three conditions an annotation must meet:

Thus, an annotation filter has three slots: types, annotators, sets. If any of these slots are empty, then it will not be used to filter out annotations. The Empty Filter has all three slots empty and therefore does not filter out any annotations.

To create an annotation filter do the following:

  1. Click on the "Instances" tab. Below the Protégé menus and the tool bar are tabbed panes. Typical tabs that you will see open are labelled Classes, Slots, Forms, Instances, etc.
  2. The Instances tab is split into three vertical sections. The left-most section displays the class hierarchy. Expand the subclass of :THING called knowtator support class by clicking the tree expansion icon.
  3. Select the class called knowtator filter.
  4. The instances of knowtator filter appear in the middle section. To create a new filter instance click the create instance icon near the top of the section.
  5. If the new instance is selected from the list of instances in the middle section, then the slot values for the new instance will appear in the rightmost section. Verify that the new filter instance is selected.
  6. Enter the name of the filter in the slot labeled name.
  7. Select the types that the filter will allow by clicking the Add Class icon above the types slot.
  8. Select the annotators that the filter will allow by clicking the Add Instance icon above the annotators slot.
  9. Select the sets that the filter will allow by clicking the Add Instance icon above the sets slot.

The following are some ways that filters are used in Knowtator: