Data can be filtered by dragging a square or circle around some points while the cursor is in the "Select" mode. The default select mode is a square, however it can be changed to a circle using the toolbar on the left of the map.
If selecting using the circle mode the distance from the center of the circle is shown at the bottom of the screen. This allows users to select by distance from a point.
Once selected the points will turn yellow can be sent to the filter by clicking the "To Filter" button on the top toolbar.