Growing and shrinking regions (1900-2010) in Spain from a population map (free access PDF): http://www.tandfonline.com/doi/suppl/10.1080/17445647.2012.744364/suppl_file/tjom_a_744364_sup_29764535.pdf



In this study Zuniga, Pueyo and Calvo (2012)  developed a complex map comprising seven provincial maps and a main municipal map, all of which are proportional symbol maps that represent two real variables: population change (represented by color hue and lightness) and total population by size. Read more