TRAVELLER: Out of the Box–Why a 2-Dimensional Map of Space?


I take a different view from many others on the issue of the subsector mapping conventions. (No surprise, I’m sure.) But I want to be clear: I’m not being dismissive of those who want to work out other systems. I simply see 2D mapping conventions working well for RPG play. (Which is the focus of my concerns.)

Basically I agree with what Victor Raymond wrote in this post, discussing how he and his group played Traveller back in the late ’70s.

The map of the subsector represented an 8×10 section of space, with each hex being one parsec across.  For anybody familiar with astronomy, this two-dimensional representation was completely artificial and unrealistic, but that was unimportant from a role-playing perspective.

For me, the Traveller subsector is a convention for RPG play. Not a representation of “real” space at all. It works to create an environment conducive to adventure and exploration for sessions of play with friends for several hours of play.

By this I mean:

  • The map provides gulfs of space between systems. These create natural landscapes of barriers, separating what can be reached easily, and what will take time and hard work to reach.
  • The map provides rare systems (A and B-starports) that provide fuel, reducing or even mitigating the risk of misjump, and words that either offer only unrefined fuel (which increase the chance of misjump) or no fuel at all (systems without gas giants) which, again, makes navigation and travel between systems separated by parsecs something that must be planned and treated as an actual expedition. [In the1977 rules, only gas giants can be used to skim unrefined fuel. The 1981 rules (and Highguard) introduce the notion of skimming from water.)
  • Offer worlds that are off the main trade routes and disconnected from the societies connected by space lanes, per the 1977 rules.
  • Make travel between worlds, when using Book 2, risky, relatively rare, and a big deal given the above, along with the risk of pirates, misjumps, hijacking, limits on J-Drives of ships, and more. While Traveller travel, the rules as written suggest and reinforce the notion that traveling even six parsecs away is a journey worthy of talking about at a bar.

All of this means that when the PCs reach new worlds there will be things they don’t know, whether it be details of the environment, changes in local politics, and so on. And then, when they turn around, they’ll be making the same calculated risk (or broad gambles) they made when they made the half of the journeys. The Age of Sails is a common reference in Classic Traveller (and rightly so). In this tradition, the Player Characters traveling half way up a subsector are like sailors make their way from England down and around the Cape of South Africa.

What this does is enforce qualities that are excellent for an RPG setting of exploration, danger, and adventure, with the Players making decisions about how to mount their travels (what gear to bring, what crew to bring, and so on, especially when they head off the trade routes). It also offers a sense of accomplishment (and honestly earned) when they head to new worlds and return safely.

None of this depends on the map being “realistic.” But it does work well to provide all these qualities. A 2D map allows Players and Referee to see all the implications and choices I mentioned in my post with clarity. A more complicated map would make these elements harder to discern.

And I wanted to add this: A quote from Marc Miller from an interview in 1981…

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7 thoughts on “TRAVELLER: Out of the Box–Why a 2-Dimensional Map of Space?

  1. Hi ckubasic – I really enjoy reading your thoughts on “out of the box” Classic Traveller but this is the first time I find myself disagreeing with you. I have always found 2D maps to be a complete suspension-of-disbelief breaker and general funkill. Your mileage will vary of course – I don’t want to suggest a 2D map is “Wrong”. But I’m knocking up a Classic Trav subsector in a 3D star mapping package designed for RPG use and it is easy to get results that are even closer to the kind of feel I think you aim for. By tweaking the probability of an inhabited system, I can set it up such that at Jump-1 (the maximum typically available to civilians in my setting), you may have to jump through one or more “barren” systems to reach your destination. The sense of colonies as lonely outposts in a vast wilderness is immeasurably increased relative to a hexgrid dotmap. The program generates whole star systems at the click of a mouse, dramatically enhancing the sense of scale in the setting. There is no way even the Third Imperium could rigorously patrol such a vast play area, let alone the Remote Interstellar Government.

    Try it – you might like it.


      • Sure – I use Astrosynthesis from NBOS. Didn’t want to come across like I was shilling for them.

        My CT setting is a 50ly radius sphere (centred on a wormhole, hence Remote Central Government). The program generates about 2000 systems for this volume, which I think roughly approximates to actual stellar density (ahem, getting my astronomy geek on)*. Average distance between systems is about 7.5ly, so I set Jump 1 equal to 7.7ly (not coincidentally the same as max stutterwarp range in 2300AD, which used a 3D map based on a real star catalogue).

        The program knocks this out in less time than it took me to write this reply.

        There is a fan-written app that will run through your sector and generate UWPs automatically according to Book 6 in a minute or so (mainworlds and colonies), but I don’t use it because I don’t like the high frequency of Class A starports and Pop A worlds with extreme tech levels. Anyway, hand-crafting the system descriptions and content based on the UWPs is the fun part of setting design, in my view. If I just want hundreds and hundreds of UWPs, I might as well play in the Third Imperium.

        *If you really want to know, I get it to generate a 45ly radius sphere and then use a fan-written app to inflate the sector by 10%, as I find this gives a better fit to real-world stellar density. I know, sorry. Sometimes I appall myself.

    • I was originally looking at a 3D map based on real stars.

      Then I started to get sucked down a hole of how much reality do you want to consider.

      And now I’m convinced Chris’s thoughts on the setting of play are worth serious consideration.

      Now I do realize that there is something wrong with a 2D universe. Fine, my hand wave solution that brings us back to the setting of play: The 2D map is not a map of actual star locations, it’s a map of jump-space. The stars may or may not be as close in real space as in jump-space, but that ONLY matters if you have STL travel, but since STL travel is NOT part of the setting of play of Books 1-3, we don’t have to worry about it.

      If I do want to feature STL, I just have to decide what the real space distances are when they actually matter.

      And presto, I’m no longer dragged into a futile realism thought process.

      And in the end, a 2D ,map is way more readable.

  2. I like the article, but I have to call shenanigans on the supposed reason given by Marc. If you played back when he started and about when I started playing, you know that it would have been insane to try and do 3D mapping. Computers were rare if non existent, and I doubt even hard core gamers had ever heard of Pythagoras. With the technology we have today, it’s really not that big a deal to do some form of abstracted 3D.. I’m looking at it myself right now, perhaps breaking up the map into larger and smaller hexes with one or multiple hexes (and star systems) inside them.. linked together in chains with perhaps variable jump ranges between them to help identify star clusters as well as elevated above and below the galactic plane.. since Marc clearly laid out that the whole map was a matter of convenience it shouldn’t really matter that everything isn’t ruler straight next to each other. Besides, todays players know quite a bit more about how space really works and I feel it might be more enjoyable for that little extra bit of, ahem, realism.

  3. I never had a problem with the 2D nature of Traveller maps back in the day, for one simple reason:

    They’re not maps of real space; they’re maps of jumpspace. And jump space is flat.

    It’s entirely possible, in that world view, to have two systems a jump-1 away from each other that are actually physically (realspace-wise) further apart than their jump-3 neighbors. They might be a huge distance away from each other vertically (relative to the plane of the galaxy) but the projection puts them next to each other, and jumpspace is a 2D place. Also very small. You still can’t exceed the speed of light … but when you’re only going a few light-days, that isn’t a big deal.

    A jump is sort of a ballistic thing — an arc from realspace up to jumpspace and back down. That takes a week. There are multiple layers of this projection, each one smaller but requiring more power to reach it. But the arc nature remains the same — if you’re going to jump-3 space, it doesn’t take you any longer than to get to jump-1 space, just more power and better technology.

    Related to this, the 2D projection of 3D space that is jumpspace seems to be limited to our galaxy — one specific, gravitationally-connected group of stars. This implies additional levels of jumpspace, presumably not accessible with “current” technology, where galaxies in a cluster would be laid out like stars in the familiar jumpspace, and a higher level yet where galaxy clusters are likewise accessible, and so on. With the proper tech level, someone could jump across the universe, working their way down by levels until they reached “ordinary” jumpspace. That is, of course, out of the scope of the game, but it’s consistent with the 3D->2D projection that makes the whole concept of Traveller jumps, and the 2D maps, work so well.

    Perfect cosmology? Nope. But good enough for games, and it makes the 2D maps make sense without needing to resort to 3D mapping software and attempts at representing 3D maps on things that can be printed.

    tl;dr: Jumpspace is 2D; it doesn’t matter where things are in realspace, it matters where they are in jumpspace.

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