What's up with the spawn generator?

If I make a custom game with, say, only five or six people, how come four or five of us spawn on one small continent?
And if I set the game settings to tropical, why does it keep spawning me in the arctic? If I set it to tropical, that's probably the exact opposite of what I where I'm aiming to spawn...:cringe: (actually the game spawns me in the arctic no matter what I do) Sometimes I try reverse psychology and set the game to cold climate - it still spawns me in the arctic...
Arid games also seem to not be very arid. I see forests, grasslands and jungles sprawling everywhere.
And if I don't like where I'm starting out, and I regenerate the map, why does it place me in the exact same type of place that made me regenerate in the first place?

So is there some kind of file I can change to make the spawn generator, you know, work?