The Term Change Tracker Plugin examines two ontologies and produces the list of edits that would be necessary to change the first ontology into the second. Normally, this tool is used on an old version and a new version of the same ontology to see what changes have occurred between versions.
The Term Change Tracker Plugin is accessed from the "Plugins" menu:
At the top of the panel are two sections labeled "Old Ontology" and "New Ontology". To load an ontology into one of these sections, either use the "Use current ontology" or "Load ontology..." buttons.
To use the currently loaded ontology as one of the comparison ontologies, press the "Use current ontology". To load an ontology from a data adapter, press the "Load ontology..." button. A load dialog will appear. Use the load dialog to load an ontology as described in Loading & Saving.
Once an ontology has been loaded into both the "Old Ontology" and "New Ontology" sections, the "Find Changes" button at the bottom becomes active. Press the "Find Changes" button to find the differences between the two ontologies. A progress bar will appear at the bottom of the screen as the analysis takes place (this can take a few minutes if the ontologies are large or there are many changes).
The results of the analysis appear in the middle of the panel:
This panel displays the list of changes in a tree view, similar to the view used in the History Plugin.
Note that if you load an ontology into OBO-Edit, make some changes, and then use the Term Change Tracker Plugin to compare the currently loaded ontology against the originally loaded file, the results will probably not exactly match the current edits displayed in the History Plugin. At first glance, this should seem strange, since both tools should be aware of the same set of changes. Both tools are displaying the a list of edits that are logically equivalent. However, the History Plugin groups the edits based on the user's activity. The Term Change Tracker Plugin is constructing the list of edits based solely on the contents of two ontologies; it can't tell if a user used the "Move" command, or whether they did a "Copy" and then later a "Delete". Therefore, the Term Change Tracker Plugin will typically display a much sparer list of edits than the History Plugin.
Once the changes have been found, they can be saved to a file by pressing the "Save Changes" button. A dialog will appear as described in Saving a History File.