Entire planet

Well over 300,000x300,000

The two mushroom islands at 16,600x16,600

Is diameter or circle distance 

Of the safe zone

Anywhere past 16,600x16,600 is consider habitable but completely unexplored and completely unsafe

300,000x300,000 is roughly what we can see 

Could easy be 3,000,000x3,000,000

Which is why and how we round the island to begin with

Rayquaza leviathan signals on radar 

Of surges

Extremely strong surges

Using space travel