Youre talking about cultures that did nothing but sea travel and youre surprised they were able to create a map? Do you htink after they set sail that they were just lost forever? lol

No, I'm talking about reproducing the shapes of the continents somewhat accurately. I've spent a lot of time on the water. You can't really tell the shape of the coast from the vantage point of being on a boat.

They didn't have airplanes, drones, satellites or even hot air balloons.

They didn't have any way to accurately know how far they had traveled. The amount of data required make that map would be astounding. I'm trying to picture the piles of hand-delivered letters and data from ships that would be required. A lot of it would be incorrect and need to be weeded out.

I'm blown away by it. I don't think it is a valid criticism of my comment that it was no big deal. Frankly I don't see how it could be done in 1587.