This page will have a guide to the treasure map you find in Anotto Bay in Assassin's Creed IV Black Flag
Treasure Map Location[edit]
The treasure map itself can be found in Anotto Bay, at coordinates (622,270), on a wooden platform:
Note: You need the Diving Bell to get to the cadaver location
Treasure Map Tool[edit]
This is the treasure map you find:
Coordinates indicate (992,422).
Note that the treasure chest itself is NOT located in Anotto Bay (where you got the treasure map from), but rather in Principe:
Dig Site Location[edit]
Note: Principe does not unlock until after the sequence 9 memory, Trust is Earned
Set a custom marker around this location at the NW side of the area:
Face these four cannons:
Turn right, and go straight along the wall until you reach a wooden face. Then turn left, and go to the edge, near the corner of a stone tower, dig location is there. See screenshots below to help you find the buried chest:
Reward is 4,000 Reales