That is exactly the method they use. Calculate the centre of economic gravity, then project it onto the closest point on the surface of the globe.
Here is a nice analysis that does the same process in a more intuitive way. It calculates the centre of economic gravity in 2D map coordinates. This gives results that are easier to understand, because everyone's used to looking at 2D maps.
Here is a nice analysis that does the same process in a more intuitive way. It calculates the centre of economic gravity in 2D map coordinates. This gives results that are easier to understand, because everyone's used to looking at 2D maps.
http://nbviewer.ipython.org/github/djv/world_economic_center...
Previous discussion:
https://news.ycombinator.com/item?id=8034394