Map_06 is a beta area in Pikmin left in the disc. This map actually appeared on an old Pikmin commercial.
Gameplay footage
This area has some internal associations missing, and had to be placed on top of The Distant Spring in order to be rendered playable. That explains the music and randomly placed objects (ship parts, enemies, Onions and Dolphin) in this video. <youtube>http://www.youtube.com/watch?v=JOLf4TJQiFM</youtube>
Geography
The map has many plants, static objects, formations in the ground, and textures not featured in the finished game. The map seems to have no real boundaries, and Olimar can easily fall into the bottomless abyss. The ground is mostly dirt with rock and grass patches about. Many textures are also in the map that were left unused in the final game. As explained above, some associations are missing, so no info about enemies and objects can be retrieved.