My understanding is that map projections are essentially complex mathematical formulae, and as such cannot be copyrighted. Would date of release/development work? This list is not complete, but includes many: https://en.wikipedia.org/wiki/List_of_map_projections Nat On 11/7/16 3:37 PM, George Carhart wrote: > can anyone tell me the best way to find a list of copyright dates for > world map projections developed in the 20th century. > > Thanks > George Carhart > > -- > > --------------------------- > Dr. George S. Carhart, Ph.D > Historian of Cartography > and Early Modern Europe > Antiquarian Map Consultant > Historic Research Consultant > > 7 Lafayette Street > Portland > ME, 04101 > USA > (207) 766-1517 >