Terraforming

Terraforming transforms one biome into another, using a vast amount of resources. Terraforming requires the Terraforming II discovery.

To terraform, first tap on a tile without a structure on it. Near the bottom-left corner, there will be an icon that will show how the tile will be changed, and the cost of changing it. Hold the icon to terraform.

Terraforming does not change ground resources. One way to farm rare materials from a Volcanic biome is to first terraform it to Rocky.

Dead planets can't have cultivatable ground, so the only terraforming available on a dead planet is from Volcanic to Rocky.