The value -1 represents infinity and is the only value with a minus sign.
Zero without a minus sign should only generate/make the starting island accessible.
I'm using the value 1 and have the starting island with one additional sector in each direction, so 9 sectors in total.
And that works. If I try to travel to the 10th sector across the sea, I get a message that I'm leaving the game area, and I believe there's an infinite ocean beyond.
The map you hold is one sector.
I guess I had a different idea what an island was? see attachment
Yes, that's the starting island, 1 sector/island... and if you also want arctic and desert, you have to enter the value 1 in the properties and then you'll also have 9 sectors/islands.
Otherwise, you only have the starting island with the default biome.
Edit: The sectors themselves remain the same size, only the number is limited. So you won't get a single sector/island with all biomes, if that's what you were expecting. 
Edit: The sectors themselves remain the same size, only the number is limited. So you won't get a single sector/island with all biomes, if that's what you were expecting.
Nope but I finally got what I was looking for 😁 see attachment
