What is a 'land type'?

A 'land type' is basically a set of ground textures used to generate the texture map, plus a set of parameters that determine the distribution of those textures. The land type distribution is stored in the attributes map, and the details of the distribution calculation may be found here.

The settings of land types are explained on the pages linked below, sorted in order of the tab on which they appear in the land type editor dialog box:

Tab 1: General	Tab 2: Parameters	Tab 3: Appearance