I see people talk about it a lot in mapart, but what does it mean?

 

Pretty sure it means your buildable island area covers a whole map with only one expansion

 

Mapart creation takes a 128x128 block area, this is the exact size of a map, map grids run differently than the island grid which are 200x200, the islands spiral out from the centre, ever expanding as more players join so not every island is capable of fitting a complete map on. A centered island is basically where the map grids fits perfectly or almost perfectly within the island grids to make it a centered island meaning it’s good for making mapart.

 

ok, how do I know if it's centered?

 

https://skyblock.onl/centred

 

this can be archived as well