Cartographer

The Cartographer, also known as a map room, is a Forerunner structure on their various megastructures, such as the Halo Array, which features a schematic of the entire installation when activated.

A central component of any installation of Forerunner construction, the purpose of a Cartographer structure is to provide a real-time holographic map which can be used to navigate the massive expanse that is an installation, along with other relevant information. The Cartographer facilities on the various Forerunner installations differ in layout and design, though the map rooms on the Halo installations are buried within large structures housing a network of compartments and rooms. Like the map rooms on most Forerunner facilities, the Cartographers of the Halo installations are protected by multiple security measures.

Installation 00
The Cartographer of Installation 00 was located on top of a massive spire structure, the map room itself lying in a wide open area giving a panoramic view over a massive waterfall. On the other side, the Cartographer structure was protected by a massive wall. The map room is somewhat larger than Alpha Halo's Cartographer structure and also much more open to the outside, though their interior spaces share many structural similarities.

During the Battle of Installation 00, UNSC and Sangheili forces breached the Covenant-held Cartographer with the aid of 343 Guilty Spark, and used the map facility to locate the Prophet of Truth.

Installation 04
On Installation 04, the Cartographer was located in an immense underground facility, below a large island. It was protected by a security system accessible by another underground facility on the other side of the island. These facilities were a part of the installation's larger tunnel network, with a massive shaft leading to the depths of the megastructure in between them. During the Battle of Installation 04, John-117 battled his way to the Cartographer in order to locate the Installation's Control Room.

Onyx
Onyx also featured a map room, deep below the Forerunner city in what the Office of Naval Intelligence referred to as Zone 67. Onyx's map center was located below a massive domed structure in the city. Below one of seven massive landing pads in the interior was a spiraling staircase which led into a smaller chamber. The chamber housed an energy bridge, which led to the map room itself; a half-spherical chamber about 20 meters across. In the center was a holographic console which could project detailed schematics of the entire Onyx construct. The room also featured a translocation platform.

Dr. Halsey used this Cartographer structure during the Battle of Onyx, when she was trying to find the way to the portal that led to the Shield World in the core of the artificial planet.

Trivia

 * The Cartographers always seem to appear over a chasm.
 * Monitors only have built-in map systems for their own Installations, (eg. 343 Guilty Spark only has a map of Installation 04) which is why the UNSC forces have to visit a Cartographer on the Ark in Halo 3, despite being accompanied by the 343 Guilty Spark.
 * The multiplayer level Construct takes place on the Cartographer building of Installation 00.

List of appearances

 * Halo: Combat Evolved
 * Halo 3
 * Halo: The Flood
 * Halo: Ghosts of Onyx