Key points from article :
Less than 15% of the ocean floor depth has been measured properly.
Competition requires system to survey 500-sq-km of seabed in a day.
Team-members cannot themselves be in the survey zone at the time.
GEBCO-Nippon Foundation team has completed 24-hour trials ready XPRIZE final.
Autonomous underwater vehicle (AUV) will create map using an echosounder.
Will be launched from the back of a robotic boat, known as SEA-KIT.