Gathered from the Web, the above 2 pictures seem to clearly indicate the night lighting from space to be an excellent proxy for GDP density.
Which can then be helpful to estimate the GDP density of countries where getting reliable GDP data is hard or impossible. Obviously not perfect as there are other variables at play such as light pollution regulations, but probably good enough for generalization.
Unsurprisingly, Africa's wealth is concentrated in South Africa and on the Mediterranean coast. It also accentuates the correlation between water proximity and GDP density (Australia, South America, China)
And North Korea (above top) "shines" as an example of where the light to GDP intensity correlation reveals a country completely outside of the world's wealth growth history. Note that South Korea has roughly twice the population of North Korea
Sources:
Earth at night from space. NASA. http://visibleearth.nasa.gov/view.php?id=55167
