The National Geological Map (MAGNA), was made between 1972 and 2003 by the Geological Survey of Spain. It is distributed in sheets 1: 50.000 (1: 25.000 in particular cases of the Canary Islands, Ibiza-Formentera, Menorca, Ceuta and Melilla). The geological map shows the nature of materials (rocks and sediments) that appear on the surface, their spatial distribution and geometric relationships between the different cartographic units represented.