Mariner's (portolan) charts provided a different world view. As Waldseemüller wrote: ". . .we have not followed Ptolemy in every respect, particularly as regards the new lands, where on the marine charts we observe that the equator is placed otherwise than Ptolemy represented it" (Waldseemüller 1907, 78). What charts did Waldseemüller have for guidance?

Besides the Caveri, the Juan de la Cosa map of ca. 1500, made by the Basque pilot who sailed with Columbus, is another possibility, as is the anonymous portolan chart of 1502 that is called the Cantino map because it was smuggled out of Portugal by Alberto Cantino, an envoy of the Duke of Ferrara. It was used by Italian and German mapmakers.

The Cantino map, like the Caveri, is made in the form of a nautical chart. Because the geography of Africa, India and the East are much superior on both the Caveri and the Cantino than they are on either of Waldseemüller’s maps of 1507, it seems possible that the "marine charts" used by Waldseemüller were of the Atlantic lands and seas only.

(For reproductions of both maps see Nebenzahl 1990, 36 and 42)