Produto Interno Bruto por km2

Em 1999, Gallup, Jeffrey Sachs e Andrew Mellinger publicaram um artigo na International Regional Science Review no qual apresentaram o conceito de "Densidade de PIB", calculado através da multiplicação do PIB per capita pelo n.º de habitantes por quilómetro quadrado. Este indicador mostra assim a "quantidade" de riqueza que é produzida por cada unidade de superfície. Os mesmos autores publicaram um mapa para representar este "novo" indicador, o qual é reproduzido acima.

Andrew Linford, no Geocurrents, aponta porém algumas limitações ao indicador e por conseguinte ao mapa:

"The data on which it is based are themselves problematic. GDP is calculated on a country-by-country basis, which leaves out regional inequalities within sovereign states.

In India especially, huge economic disparities are ignored, which makes it appear as if Bihar were more economically productive than western Maharashtra just because it is more densely populated. Also, the level of resolution vastly varies across the map. For example, the United States is mapped largely at the county level, which provides a fairly detailed portrayal, whereas Russia is divided into much larger areas, mostly oblasts. As a result, Russia’s Arctic coastline is depicted as having much higher levels of economic activity than is justified.

Finally, low-population areas that have highly productive mineral economies are left off the map. The mining zones of northwestern Australia, for example, produce a significant portion of the country’s wealth, yet one would never know this from the map."