In wc3, this was a skill owned by the Far seer, called Far Sight. and it pretty much gave vision in a circle of where the far seer clicked on the map. and anyone with vision of that location saw the particle effect.
In TrollsAndElves, it is just called Reveal, and is used on larger maps so the Troll can search two bases at once.
http://i.imgur.com/KNYFMNS.jpg for reference.
In wc3, this was a skill owned by the Far seer, called Far Sight. and it pretty much gave vision in a circle of where the far seer clicked on the map. and anyone with vision of that location saw the particle effect.
In TrollsAndElves, it is just called Reveal, and is used on larger maps so the Troll can search two bases at once.