According to the time line what has caused changers in map makeing over time

The Lend-Lease Act stated that the U.S. government could lend or lease (rather than sell) war supplies to any nation deemed “vital to the defense of the United States.” Under this policy, the United States was able to supply military aid to its foreign allies during World War II while still remaining officially neutral in the conflict. Most importantly, passage of the Lend-Lease Act enabled a struggling Great Britain to continue fighting against Germany virtually on its own until the United States entered World War II late in 1941.