Figure 8. To show the relationship of the designation as primary or secondary to the joint distribution of SChDD and ΔIF.

The joint distribution is shown of the values of SChDD and ΔIF for the 72 units which could be identified as primary (•) or secondary (○). Note that the secondary units are restricted to quadrants 3 and 4, whilst the primary units are predominantly in quadrants 2 and 3.