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 and an ocean. Facing the desert on the other side, the Cartographer structure was protected by a large wall structure. Inside the wall was a deep chasm and an energy bridge allowing passage over it. A terminal was located within the wall near the activation switch for the energy bridge. The interiors of the Ark's Cartographer share many architectural similarities with Alpha Halo's Silent Cartographer shaft, although the two are considerably different in general layout.

When the UNSC and Sangheili forces landed on the Ark during the Battle of Installation 00, they were prevented access to the Cartographer by its exterior wall. After the Forward Unto Dawn landed nearby and deployed a convoy of multiple vehicles, Commander Keyes suggested they go through the wall. The UNSC forces returned to the wall and with the assistance of 343 Guilty Spark, successfully passed through. The UNSC and the Sangheili 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

 * Monitors only have built-in map systems for their own Installations, which is why UNSC forces must visit Installation 00's Cartographer, despite being accompanied by 343 Guilty Spark.
 * The multiplayer level Construct takes place on the Cartographer building of Installation 00.

List of appearances

 * Halo: Combat Evolved
 * Halo: Combat Evolved Anniversary
 * Halo: The Flood
 * Halo: Ghosts of Onyx
 * Halo 3
 * Halo 4