The Galactic Map was the most treasured possession of the thief Hogey the Roguey. The Galactic Map was first owned by the Simulant Generals, from whom Hogey stole it, and later came into possession of the boys from Red Dwarf.
The Galactic Map was an old rag or piece of cloth, but on which was inscribed the co-ordinates of everything of note in the Milky Way - for example wormholes, Earth and other S3 planets, old Space Corps bases, and derelict starships.
It is possible that the Simulant Generals made the map from prowling around the Galaxy looking for humans over the last three million years; another possibility is that the Simulant Generals copied the map from an earlier Space Corps star-chart.
The Simulant Generals also prized the map, enough to chase the thief for it anyway. It is likely the map was being used by the Simulants in their hunt for any surviving humans in the Galaxy.
Hogey came aboard Red Dwarf and offered the map to the boys from the Dwarf if they could beat him in one of their many "duels across time and space", in this case a cookery competition suggested by Arnold Rimmer. Hogey said that they would never have seen the likes of the Galactic Map, and Lister replied that Hogey wouldn't believe the likes of which they'd seen.
However, the Simulant Generals had followed Hogey to Red Dwarf, and began to shoot missiles at the hull from their Annihilators. A fissure formed in the sleeping quarters causing a depressurisation, but Hogey fell against the wall, sealing the crack up. Lister took Hogey's Molecular Destabilizer and the map, and the crew fled Red Dwarf on Blue Midget.
After learning his true parentage from the holo-lamp, Rimmer came up with a successful plan to eliminate the Simulant Generals using the Molecular Destabilizer. Back aboard the now-safe Red Dwarf, Hogey's brother appeared, saying "you kills my brother" and challenging Lister to a duel across time and space, much to Lister's exasperation. The map itself is not mentioned again, but there is no indication that the crew don't have it. ("The Beginning", Series X)
- Although Hogey said that it would "lead them to treasures the likes of which you have never seen", the Galactic map is not mentioned again in the following Series XI. However, although it is not mentioned, it is possible that the Dwarfers are using the map in Series XI, since they seem to be moving through much more populated regions of the Galaxy as opposed to Series X. For example, it is possible that the Galactic map led the Dwarfers to the wreck of AS Thanatos in the first episode of XI, where they discover the Casket of Cronus, and so on, such as leading them to Asclepius' Station etc.