The Sea Chart is a gameplay mechanic in Sonic Rush Adventure. It depicts a significant portion of Blaze's world and serves as a route planner where the player is able to plot a route on the sea to travel along during the Sea Stages of the game and/or to visit an island to play its Act Stages.
The Sea Chart's appearance varies slightly on whether the player access it via the "Set Sail" option or the "Sea Chart" on the menu. In both cases, the Top Screen displays a small map depitcing all islands (Act Stages) the player has visited; all main islands are represented by unique-colored dots in comparison to the smaller light-blue dots representing Hidden Islands. In addition, Miles "Tails" Prower is present to interact with the player.
The Touch Screen displays a close-up of the player's surrounding sea areas, displaying every island each with a unique icon and discovered Johnny's Race stages with an icon of Johnny's face (a red cross over it indicates that the player has cleared that particular race). On the Touch Screen of the Sea Chart, the dark blue sections indicate areas not explored by the player while other shades of blue represent explored sea sections. Sometimes, explored sea sections exhibit unique colors, usually around certain islands related to those islands' climate (such as icy blue nearby Blizzard Peaks).
In gameplay, the Sea Chart is used to plan sea routes for the selected vessel to travel along for the Sea Stage. The player can move the view of the Sea Map by using or dragging it with the Nintendo DS stylus. The player can also zoom out/in on the map in three different scales by pressing L/ respectively or by touching the zoom buttons on the bottom-right corner of the touch screen. When accessing the Sea Chart via the docks and selecting "Set Sail", the selected dock's vessel is highlighted in blue.
To draw a route on the Sea Chart, the player must use the stylus to draw from a starting location, typically from main island Act Stages (marked with an orange dot and the tip of a ballpoint pen) to a certain point on the Sea Chart. The player is limited to the distance which it can travel (represented by an "ink" gauge on the top-left corner of the Touch Screen that depletes as the route is sketched). When drawing a route, there are also pink area details which indicate areas that the selected vessel is unable to travel across due to shallow water, rocks or icebergs. To reset the route, tap the yellow button with a blue cross. Once a route is finalized, tapping the yellow button with a red circle and confirming the route leads automatically to the Sea Stage.
If the player come across obstacles inhibiting their vessel from proceeding during the Sea Stage, they will be sent back to the Sea Chart to divert the route somewhere else.
During the game's story, the Sea Chart may indicate areas the player must travel to. These are marked with an orange flag with an exclamation mark that usually lead to a new playable island.
While on Southern Island, the player can access the Sea Chart via the menu (opened by pressing ). Here, the Sea Chart can only be used to visit islands previously explored by touching the green icon of the island. If the selected island is an Act Stage, the player can play through all of its Acts consecutively.
- The yellow buttons used to confirm or reset the sea route both resemble / buttons respectively on the PlayStation consoles.
- If the player sails to Sky Babylon via Sea Chart, they will enter Hidden Island 2 instead.
- In order for the player to enter Sky Babylon, they should visit the Sea Chart via the menu on Southern Island.