Fedea (Fundación de Estudios de Economía Aplicada) is an economic think tank financed by a large set of big Spanish firms. In November 2014 it published “Personal revenue in Spanish municipalities and its distribution” (Miriam Hortas Rico and Jorge Onrubia Fernández). Fedea’s website includes two maps in which you can visualize, by municipality, revenue and inequality as expressed through the Gini index (the closer to 1, the most unequal). The results are based in micro data from the Personal Revenue Tax 2007, for the 1.109 municipalities over 5.000 residents, and the project would extend that series over time.
The use of a gradient of the same hue is not always helping reading the map; the most important thing is, as in any map, the underlying data, but I think there are better ways to visualize that worrying content (it is worth reminding that these are 2007 data, and the current crisis doesn’t seem to have improved the situation). That is what I have tried to do, using the database published on the web. Maps show quintiles.