A Holo-tank as seen on Yavin 4.
Holo-tanks functioned as devices that projected a holographic image, giving anyone watching the feeling of actually being "inside" the displayed image. They were essentially three-dimensional visual projection areas, similar in shape to a small amphitheater. The design of a holo-tank was fully circular and set into the floor. Those observing would stand around the perimeter and look downward into it. The main use of holo-tanks was in military command centers, where they were used to monitor tactical movements. Targets appeared as simple points of light, positioned accurately in a scaled-down representation relative to a specific reference point. To easily pinpoint targets, a three-dimensional grid system was digitally overlaid onto the holo-tank's projection field.
