| The centrality value here is a measure of how close each nation is on average to all other nations. By close, I don't mean actual distance. Instead, I mean in terms of the fewest number of nations one must pass through (via land borders) to get from one nation to another. To get from France to Germany, you of course only cross 1 border. To get from France to Poland, you must go through Germany and Poland (2 borders). To get from France to Russia, you go through Germany and Poland and into Kaliningrad (3 borders). So you figure out how many steps it takes to get to every other nation from France, average the number of steps per nation, and you get the centrality value. So France is on average 4.803 steps away from every nation which can be reached by crossing land borders (152, including itself). Repeat for each nation. France happens to be the most central nation mostly by virtue of French Guiana, which is the only link between the Americas and Afro-Eurasia. So any nation in the Americas must pass through France to get to a nation in Afro-Eurasia, and vice versa. (Despite its being an island nation, the UK is connected to Spain via Gibraltar, so the UK is part of the 152-nation network.) The 40 UN members which are not included are island nations, with no land border shared with another nation. Included in the 40 are Haiti and the Dominican Republic, which do border each other, but are not part of the greater network. |
G8 (+5) Leaders 
Most Populous Nations 
Least Populous Countries
