Filters remove unwanted periods of data from any search and subsequent analysis.
Data acquired between batches can be included in any search for a signal contained within genuine process data. Subsequently, transition data can be incorrectly highlighted as containing a signal of real interest. Filters are used to exclude selected time periods to prevent ingenuine data from interfering with carefully considered signal searches.
Filtered periods are not taken into account while performing a search.
- To find very specific operating conditions, combining multiple searches.
- To neglect certain periods in other analyses such as table comparison, scatterplot, and influence factors.
Two types of filters can be created:
- Time based filters filter out specific time periods. They are not automatically updated based on process conditions.
- Criteria based filters are linked to a saved search and will be updated when the conditions of the saved search are met in the future.
Time based filters are defined as a set of time periods that are excluded from the data set. Periods can be added to the ad hoc filter manually or from the search results list to exclude them from the data set. The ad hoc filter is empty by default, meaning that all data within the double slider selection is taken into account for further data analysis. When a filter is applied a small blue dot appears next to the filter icon with a number highlighting the number of filters being used.
Manually filter out time periods
- Select a time period in the focus chart.
- Use the filter icons to exclude or include the selected time period. Including a time period will only have an effect when at least part of the selected area is currently excluded by the ad hoc filter.
- When excluding a time period, the selected time period is added to the ad hoc filter submenu and greyed out in focus chart and context bar.
Filter out periods from a search result list
- Use the filter icons on the left of the search result panel to keep or exclude results.
- Select the results you would like to include or exclude.
- Confirm to update the ad hoc filter.
Note: will exclude all selected time periods. will include the selected time periods and exclude all other time periods.
Save the ad hoc filter
Although the ad hoc filter is mainly used for ad hoc filtering purposes, it can be saved as follows:
- Navigate to the filter menu.
- Select the ad hoc filter by clicking on 'Ad hoc filter'. The details of the filter show the time periods that are excluded, as well as a 'Save' button.
- Press the 'Save' button to open the 'Add time filter' form.
- Give the filter a name and press 'Save'.
- The saved time based filter is now available in the 'Filter' list, and can be toggled on or off using the corresponding toggle button. The time icon in front of the filter name indicates it is a time-based filter.
A saved ad hoc filter can be removed using the delete icon on top of the filter menu.
Note: Since the ad hoc filter contains specific time periods and is not coupled to search criteria, it will not be updated based on future search results. For this purpose, criteria-based filters (see further) can be used.
Clear the ad hoc filter
The ad hoc filter can be cleared as follows:
- Navigate to the filter menu.
- Select the ad hoc filter by clicking on 'Ad hoc filter'.
- Press the delete icon on top of the filter menu. The filter is emptied and should now indicate no time periods.
Note: Saving an ad hoc filter does not automatically clear the ad hoc filter, nor does it enable the newly saved filter.
A criteria based filter is linked to a saved search. This means the time periods that will be filtered out are not fixed, but depend on a search criterion.
Create a criteria based filter
Criteria based filters are created by coupling a derived filter to a saved search:
- Define the search criteria of interest via the search menu.
- Press the save icon in the search panel to save your search.
- Name your search and check the appropriate boxes under 'Create derived filter' to either filter out the results of the search or filter out everything else. Click the 'Save' button to save the search and create the derived filter.
- The criteria based filter is now available in the filter list and can be toggled on or off using the corresponding toggle button. The icon in front of the filter name refers to the search type (e.g. similarity search, value based search, etc.) the filter is coupled to.
Removing or editing a criteria based filter
A criteria based filter can be removed using the delete icon on top of the filter menu or by removing the saved search it is coupled to. To edit the filter conditions, you need to edit the conditions of the saved search in the search menu.
Switch filters on or off
Filters can be toggled on or off via the toggle buttons in the filter list. Every time the filter is switched on, the corresponding search is performed and time periods are filtered out based on the search results.