Areas and why Warehouse says too many of type in area?

[CaptainDraven 0]

I've searched an entire island, especially the beaches, for any other warehouses. I can't find any.

I also mapped out the distance and the attempted placements are all outside of the 600m radius for other warehouses.

Is it possible there's a max limit of mines/farms etc that prevents the placement of another warehouse?

For instance an area might have maximum of 5 types of similar building and an area = what exactly? 

Is it that an area is a "grid" and can have too many such buildings in existence or what?

 

Thanks!