What are erosive forces?

[Defiant47]

Simple question, please answer.

This pops up when you customize the map, asking you for cloud cover, native life forms, ocean coverage, and "erosive forces", represented by 1 to 3 moons (weak to strong).

 

[vyeh]

The greater the erosive force, the less mountains (higher elevation).

From p. 9 of the manual:

Erosive Forces

Allows you to choose between Strong (rolling and flat terrain), Average (hilly terrain), and Weak (rough, mountainous terrain). In general, flat terrain is easier to settle and terraform. Rougher surfaces are harder to terraform, but offer an abudance of mineral resources.

 

[Elliot]

Weak erosive forces will also give you more land on the map since the mountains expand into the water.