Random maps are often the core of single and multiplayer gameplay, aside from story based campaigns that are often shipped with the game.
Methods for generating such maps vary depending upon the topography of the game itself.
Random maps can also be used by scenario designer to unlock previously unavailable units.
For example in Age of Empires II, designers have used RMS to unlock new terrains and units.
Another example is Empire Earth, where an unused dark red coloured cliff can be unlocked through a custom random map script.