There is a political view of Columbus' map error that is easily outlined.
Brian says, "From: "Brian O'Neill" <email@example.com>Date: 28 Aug 00 06:15:36 -0400 (EDT) Subject: Columbus's "Error" was almost fatal
The problem with Columbus's map can only be understood outside of the map itself, in politics. Toscannelli's map was correct mathematically, but the project was obliged to rely on Venetian sources for the actual size of China or Asia. So Cipango, japan, was drawn on the map using a deliberately over estimated size.
Now place yourself in Columbus's shoes. He stored aboard enough supplies to reach Cipango according to the map. Venice for sure expected the expedition to fail by starvation long before it reached Cipango.
Then imagine the consternation in Venice at word of their successful return. Venice opposed the whole project as they had a vice-grip on eastern trade and faced loosing that.
So a mathematically correct map with good earth-size estimate, and deliberately false information resulted in a genuine discovery of an entirely new continent. Columbus himself refused to believe it was not Cipango. So Venice doubly lost the whole farm, and Europe gained greatly.
So history is made.
However, Bishop de Landa modified Columbus' log books in a manner that there is no primary data base to confirm Columbus' actual longitude computations. During Columbus' three trips, two eclipses were observed and recorded. The third trip's eclipse is very well recorded, as Columbus carried its prediction for European appearance, and therefore had to know his actual longitude to a high degree of certainty, less than 1/4th degree.
These trip log books of Columbus have never surfaced, in Columbus' handwriting, and there is a vivid political reason for it. Bishop de Landa modified the reading of the Armed Guards of Polaris, a well known Portuguese star clock time reference system (on the first voyage's log book), as well as burning Mesoamerican codicies for reason of another type of censorship. In this case if the actual longitude would have been known in the 1490's, any maybe for many years thereafter, the Spanish-Portuguese Treaty agreed upon by the Pope in 1494 would have been broken, with Portugal owning most of Hispanola and other newly acquired Spanish lands.