Fog of war

The Fog of War is the idea that in war you have little knowledge of any enemy actions that occur out of your site.

In Empire Earth this is portrayed in that any place on the map that no friendly units have visited is black and you can't see any units, terrain, nothing that is there (Obscured). When a friendly unit visits a location, the area comes in to full view (brightly lit) - units, terrain, etc. When the friendly unit/s are no longer in that area, the area becomes darker (shaded) and you can only see the terrain and buildings that were there at the time the unit/s were there.

Depending on the set, the reveal map option for hosts is used so the total blackness is gone - the terrain is fully visible to all players.