Oracle of SeasonsLink can purchase the Treasure Map at the back of the Horon Village Shop for 200 Rupees once he purchases the Member's Card at the Subrosia Market. It shows the location of the four Jewels scattered across Holodrum that, once obtained, open the gate blocking Tarm Ruins.
Treasure Maps are also found in Phantom Hourglass, but they act similar to the Treasure Charts in The Wind Waker. These maps have a pink color, similar to the Special Charts in The Wind Waker. There are 31 maps in this game, and they show Link the location of hidden treasures that lie at the bottom of the ocean, which he can retrieve with the Salvage Arm. The treasures inside these hidden chests are usually Sand of Hours, parts for Linebeck's ship, or large quantities of Rupees.