The Royal Dutch Geographical Society (Dutch:Koninklijk Nederlandsch Aardrijkskundig Genootschap; KNAG) is an organization of geographers and those interested in geography in The Netherlands. It has about 4000 members and sponsors lectures on geography. It publishes a scientific magazine, Tijdschrift voor economische en sociale geografie (Journal of Economic & Social Geography) and Nederlandse Geografische Studies or NGS (Dutch Geographical Studies). It also has a large collection of about 135,000 maps and 4500 atlases which have been housed at a library at the University of Amsterdam since 1880.