But remember also that northern hemisphere navigators like the Portuguese also had to align their maps in a different direction as they crossed the equator and lost their main reference star on their way around Africa.
They soon discovered how to navigate by then aligning with a group of stars called "Cruzeiro do Sul", the Crux constellation[1], which means that it could be reasonable to actually start aligning the maps southwards (and the portuguese were the ones mapping the whole coast of Africa at the time).
But I guess that by that time (around the 1470s), they were already too used to aligning northwards...
They soon discovered how to navigate by then aligning with a group of stars called "Cruzeiro do Sul", the Crux constellation[1], which means that it could be reasonable to actually start aligning the maps southwards (and the portuguese were the ones mapping the whole coast of Africa at the time).
But I guess that by that time (around the 1470s), they were already too used to aligning northwards...
[1] http://en.wikipedia.org/wiki/Crux
Edit: I meant northern hemisphere navigators, instead of northern european.