Understanding shape filters
Let us look how at the different options and features available at your disposal!

Creating:

What kind of shape filters can I draw?

There are two options to draw these shapes: either using a rectangle(default) or a custom polygon, according to your need.
Drawing a polygon shape filter
That’s it! It's that simple!

Exploring:

What do I see after drawing the shapes?

Simply hovering your cursor over a given shape will show the selected metric of the given shape. The topmost metric is set as the default in this case.
The different shapes drawn can then be clicked on to view the entity lookup of the shape which includes a vast number of metrics(revenue, trip duration, etc.) from which the user can choose from. These can further be sorted and filtered according to need.

What do filter areas and aggregate options do?

Once you draw your shapes, you can click on the 'shape filters' tab at the top. It consists of two options: ‘filter areas’ and ‘aggregate’.
Filter areas allow you to individual aspect the sub-areas(hexes) enclosed within the shape. This would enable a more microscopic focus on the respective shape. You can now see which areas contribute the most and least in your drawn shape(s).
The aggregate on the other hand, as its name goes, shows the aggregate(sum total) values of metrics within the shape. This is the default option you see once you draw the shapes.

Can I integrate this with GeoJSON file?

Your consoles can already download existing visualization in GeoJSON format to visualize on external applications. With shape filters now you can download only specific areas of the map/visualization as GeoJson Files. These can then be exported.
Aggregated view of shapes
Shapes with 'filter areas' toggled on
Exporting as GeoJSON file