This "octant" map is dated approximately 1514. The sphere
of the globe was divided into eight equilateral spherical
triangles, each section bounded by the equator and two
meridians 90% apart. This was the first map of its kind. It
is noteworthy for at least two other reasons: (1) it was one
of the first world maps that used the name "America," and
(2) it was one of the first world maps to lay down a
south-polar continent. Some critics believe the map was not
really a work by Leonardo himself, since the accuracy and
mastery in drawing are not reflective of da Vinci's usual
high standards. It was more likely done by some trustworthy
clerk or copyist under da Vinci's employment.
