terrain.noise_base_landIsland shape

Think of this as the map's population layer. It doesn't set height directly it decides what each part of the map is allowed to become, the lowest spots turn into ocean or lakes, just above that you get beach, then plains, then hills, and only the best spots can grow mountains.

Raise amp and the terrain swings harder taller snow-capped interior and deeper bays while the island outline barely moves. Raise freq for a denser patchwork of lakes and hill clusters.