Historical Belem: Mysterious Map Hunt

You are a Portuguese sailor who works the spice trade route, returning home from a long journey to India. While you were there, you met an old Sadhu (Hindu holy man) who gave you a mysterious map and said that if you followed it across the waves, it would lead you to great treasure.

After hearing so many exaggerated tales from your fellow sailors, you don’t believe a word the Sadhu said. But this map looks ancient and is covered with strange symbols, perhaps you can sell it for a few coins?