When to use 世界 and when to use 国际
I guess you just use them the same way as in English.
Look at e.g. this list:
Everything that uses 国际 translates as 'international'. Similarly in this list everything that is 世界 translates as 'world'.  

A map that shows all the countries and their GDP (as a choropleth) would be:


  世界GDP分布图


In the case of a poverty average, I think you would rather use global poverty or 全球减贫 in Chinese.