Geostrategic power index - variable 3: Nuclear weapons

The third variable visualized and included in the calculation  of my geostrategic power index is nuclear weapons. The nuclear weapons variable indicates simply if a country have nuclear weapons yes or no. It does not take into account the number of weapons in the inventory or what kind of carrier is available to deliver the payload (air,sea,ground launch). My view is that nuclear weapons possession is a real power indicator wether we like it or not, why else would most of the world be so anxious to stop Iran developing "the bomb" and what respect or impact would North Korea have on the rest of the world if they did not have the bomb.
The Nuclear weapons map visualizes the 8 countries currently in possession of nuclear weapons. Click on images to see which countries.
Ukraine and South Africa, have previously been in possession of nuclear weapons but opted out of the "nuclear club".
The map also shows that the world centroid or center of gravity for nuclear weapons is located in central Kazakhstan.