Mapa de vulnerabilidad al la Contaminacion de los Mantos Acuiferos de la Espana Peninsular, Baleares y Canarias.
Instituto Geologico y Minero de Espana
Notice how the color distinctions within this map portray information beyond border distinctions? In modern mapmaking, color is increasingly used as a method of communicating different types of data. The oranges, yellows, greens, and blues in this map depict the level of vulnerability to pollution of groundwater from mainland Spain, Balearic and the Canary Islands. This map can be found here.