Line of sight

From GenieWiki

Line of sight (often abbreviated to LOS) describes how far a unit can see. This distance is normally greater than the range of the unit and is measured in tiles. Black areas of the map represent unknown territory that has not been explored, in other words tiles that have not been revealed by a units LOS. Areas that are not currently in any objects LOS are covered by the fog of war. LOS (including that of allies) is the only way the map can be revealed without using cheats.

Most objects, including buildings, have a line of sight, however some have 0 LOS. For example the mercenary and blind lame priest units in Age of Empires are effectively 'blind' and must rely on other units LOS to be visible. Other units have a variable LOS, for example monks carrying a relic in Age of Empires II have a smaller LOS than those without one. Objects with a large line of sight make excellent scouting units, especially combined with good unit speed. The scout unit (scout cavalry etc) is specifically used for this purpose, with only minimal capabilities in combat. LOS can often be upgraded by researching certain technologies.

Military units generally attack enemy player units as soon as they are within their LOS. Some units will not do this, or can be instructed not to (e.g. setting stance to stand ground). Gaia units become property of the human players as soon as they are sighted by any unit of that player.

Age of Kings

The follow command in Age of Kings will task a unit to move towards another unit so as to keep it within its LOS. The outpost building in AoK is specifically created for its long line of sight and serves no other purpose. The spies technology allows players to see enemy line of sight. In the object visible condition the object must be visible to the player on screen - if it is in their LOS but off-screen the condition is not met, while if they use marco-polo instead the condition is still met - a handy way to tell if the player is cheating.