One of the largest collections of rare and historical maps in America is being donated by a California real estate developer to Stanford University. David Rumsey, who has spent 30 year amassing the huge collection of 150,000 maps, has created one of the premier cartographic collections of American history in the United States. By giving the physical maps, their digital images and his database to Stanford, Mr. Rumsey hopes to encourage other donors to give their original pieces along with digital copies at the same time.