Using filters

Spotfire's inbuilt filters offer a very powerful and immediate way to start analyzing your data. Every time you add a data table to an analysis file, Spotfire creates a filter for each column. Just reflect on this for a minute: if we are going to try to filter or screen our data in some way, we have to do so on the basis of the values in one or more of the data table's columns. That is why a filter always corresponds to a table column and its values to whatever data currently populates that column through the rows in the table.

You can access filters from the data panel (by clicking the button on the left-hand side of the Spotfire window) or the filters panel. The filters panel shows all current filters and their current settings. You can show and hide the filters panel from the View menu (View | Filters) or by clicking on the filtering icon on the toolbar. The following example will use the data panel, but it’s just as valid to use the filter panel:

1. As we mentioned previously, the data panel is divided into numbers and categories. If we had date or time columns, location, identity, or other types of columns, these would be categorized as such.
2. Let's filter to first-class passengers only. Locate the pclass column and click on it to highlight it. You'll notice that a funnel icon will be shown:
   
3. Click the funnel—you'll see a pop-out filter appear, so unselect pclass 2 and 3. Watch how the visualizations change as you do this—they'll all update together as they are showing the same data:
   
4. Let's look at how this leads to fresh insights. Select all the females in a main visualization chart—the histogram should look like this:

1. Look at that! If you were a first-class female passenger, you were almost guaranteed to survive.
2. Reset the filters by clicking the Reset all filters button at the bottom of the data panel. Feel free to play with the other filters in the meantime to see how they affect the data:
   

An important point to stress at this juncture is that we haven't removed any data from the underlying table. Our visualizations have changed and "lost" some rows, but as you saw, when you reset the filtering, the visualizations adjusted dynamically and displayed all the data.