Scope and format of system and world data sheets


Here are examples of a star system data sheet and a world data sheet for a world in Flat Black. Are they nice to have. Ought they to be omitted? Simplified?

A lot of the time that answers are “mostly not, but sometimes”.

The moons of the gas giants usually don’t matter, but sometimes object VIIa is a sulphur moon, which suggests valuable chalcophile minerals, space mining, a local space industry or conflict with the Empire over mining rights and space access. Sometimes there’s an ocean world that could be being terraformed. Sometimes there’s a second garden world.

But honestly the system sheet is mostly there because always since I was using ForeSight, and still now that I’m using GURPS Space the system sheet has been produced in the process of generating the system, so it costs nothing to show it. I think that some players are reassured by seeing it, that it gives and impression that the information that would be there for their characters to look at is actually there. But I can’t say that I’ve ever asked. Showing the system record is mostly just a habit, I think.

The name of the star, and the world’s systematic identifier (e.g. “Tau Ceti III”) don’t actually matter, but I really think they need to be there for verisimilitude. It’s like an NPC not knowing his own name — a painful hit to the suspension-of-disbelief if the information is not to hand.

Spectral class of the star, its luminosity, and the planet’s orbital radius. Hmm. It’s really just one of those things that everyone would know. It would certainly be in an in-setting document, so its presence contributes to verisimilitude. I guess it could be cut. Am I right to be reluctant?

The axial tilt (obliquity, dammit!) provides an important hint to seasonality, and it is something that I always consider when I am going to set an adventure on a planet. It informs a lot of my descriptions of architecture, clothing, and the countryside. It makes me think that I might set an adventure in winter or in summer, and gives me ideas about what that might be like.

The year length. It’s like an NPC’s name. It’s just something that everyone would know, that a GM shouldn’t need two minutes and a calculator to answer the question about.

Length of the local day. Yes, it’s usually 18–24 hours and doesn’t make a lot of difference. But PCs often ask “how long to nightfall?”, “how long until light?” for planning tactics. And a very long day like Tau Ceti’s or an unusually short one sometimes drives significant cultural detail that will determine, for instance, NPCs’ schedules and whereabouts.

World type. It’s nearly always “standard garden planet”. Very rarely “standard garden moon” or “large garden planet”, and when it is, that’s always apparent elsewhere on the sheet. I guess it could go.

Diameter. (a) It seems like the sort of thing everyone would know about and document. I can’t imagine it being left out of an in-universe document. It gives players a bit of context for the population numbers. I sometimes (rarely, I admit) take note of it to describe the horizon as being distant or close, and to estimate whether the planet will be windy. I don’t know about anyone else: I’d just feel stupid not knowing whether the adventure were on a large world or a small one.

Density. Not necessary when the diameter and surface gravity are giving. Some players I have known to guess that high density means mineral wealth and low density means mineral poverty. But I could cut this entry.

Surface gravity This actually is mechanically significant in both ForeSight and GURPS, and in ForeSight it can make a big difference to several important adventuring and combat skills, including Athletics and Mêlée Combat. It influences my descriptions, including my descriptions of architecture and engineering works. It is economically significant because of its effects on the shuttles needed for off-world trade. And I just can’t imagine not knowing.

Escape velocity I did without this for decades. I was fudging. Obviously I could manage again.

Period of low orbit Hang on. What happened to period of low orbit? I was sure I had put that in. Again, I could manage without it by assuming that launch windows and drop windows for backup always recurr every ninety minutes, that an orbiting ship or satellite ist always below the horizon for eighty minutes or so.

Vulcanism and tectonic activity. I use them to get an idea of whether there is mountainous or low relief, whether soils are fertile or poor. But I did without them when I was using ForeSight and could again.

Climate I could do without the “climate” category descriptor, but the surface temperature descriptors matter to me. They let me know whether to place habitation at the equator and describe icecaps or at the poles and describe deserts. That’s a pervasive influence on culture. I did without perihelion and aphelion extreme values, but that was before i had to contend with the large eccentricity values that GURPS Space assigns planets.

Ocean coverage. Again, I can’t imagine describing a planet and not mentioning this. Besides, it makes an important contribution to the context of population and prpulation density figures, and informs me whether to think of deserts or farmland. It’s always water, though. I guess the composition can be cut. Tidal range. I like knowing whether to describe large tides or none.

Atmosphere. Well, the main gases are always N2, O2. Except in the rare cases when there’s He as well. I guess it can go. And *class is always breatheable except in cases when it is marginal. But I want to put “tainted” “oxy-toxic” and “narcotic” description in here in future.

Sky objects, their periods, apparent sizes, and tidal components. People were pleased when I added these, though I understand that it doesn’t actually matter how the moons look.


Well, I used something very like this in my own Wives & Sweethearts (derived from your sheet, in fact). Here’s an example.

That had what I wanted as a GM.


Is this for the players or the GM? I have no doubt that a lot of this is needed for the GM to understand the colonial environment.

However, I thought the current push was to create a bunch of approachable player briefs. While you are correct that digital pagespace is effectively free, attention can easily be broken by two pages of scientific data.

Perhaps an appendix?



The current push is to create a document in which there will be about quarter of a page (150 words) each about perhaps sixteen or twenty, possibly as many as two dozen, example worlds. To carry out the plan I need to select the examples, complete worthwhile designs, and then draft, revise, and polish the prose until it fits into a due word-count. But I haven’t actually been working on that for about three weeks, for what seem like reasons but that I know aren’t really. Instead, I have been trying to stop the fire from going out.

Eventually there ought be some sort of separate product, perhaps a pair of gazeteers (Central Sector and one outer sector), perhaps a database, perhaps a generator with a fixed PRNG that provides players and GMs with a brief to examine about a chosen homeworld or setting for a particular adventure.


Ah, understood.

In that case, doing the full write up for a thing and then pruning to the bits that are proper in context is a time honored way to craft credible settings.


I like to know density because I can derive surface gravity from density and diameter, which makes it seem less arbitrary. That way I have more confidence in the physical plausibility of the setting.


Furthermore, you can easily derive the period of low orbit whenever you need it from the fact that it is proportional to the cube root of density. This saves you from having to make tedious comparisons between the escape velocity and the diameter of the planet.

I am suddenly struck by the cogency of reporting the escape velocity as a multiple of vesc instead of in silly old kilometres per second.


The question arose in the thread about Navabharata as to what the “equality” rating means. The answer is that I am using one minus the Gini coefficient (of household income per household member)

The rationale is there is a convention (now going out of fashion) of using that as a conversion factor to turn GDP per head into “standard of living” for international comparisons. The problem is that it’s completely obscure. For anyone except some economists you have to define the Gini coefficient, and though I know how it is defined it really doesn’t communicate anything even to me.

So, what are the alternatives?

  • A 10% Rich/Poor ratio? (e.g. the income of the richest 10% in Australia is about 12.5 times that of the poorest 10%. The corresponding figure for Denmark is 8.1, for the USA 18.5, for South Africa 33.1 and for Bolivia 93.1).

  • A figure for X% of households earn 100-X % of all income? (50% earn 50% at perfect equality, 0% earn 100% at perfect inequality.)

@whswhs suggests a scale of 0–6 of qualitative descriptions set out in a key, like “Control Rating” in GURPS. I’m going to have to think about whether to provide a scale of equality or of inequality, and have a care to write the descriptions so as to indicate inequality per se and not the material misery of the poor etc.

0–6 seems like a strange range to me. I would naturally think more of a scale of zero to ten, or of no stars to five stars. I could be done in a text document like this: ★★★☆

And then I had a really ditzy idea. Emoji!

Tau Ceti could be: 🥴:frowning:️:neutral_face::neutral_face::neutral_face::neutral_face::grinning::man:‍🦳:older_man::face_with_monocle:

Navabharata could be: :rage:🥺🥺🥺:frowning:️:frowning:️:frowning:️:neutral_face::grinning::clown_face:

What could convery more than that? It only emoji didn’t look all alike.


Well, emoji surely won’t work for me, as I can never figure out what the expressions are supposed to mean. When I read an e-mail or newsgroup post with emoji I just don’t even see them any more.

I like 0-6 because it fits the cognitive psychologists’ idea of “the magical number seven, plus or minus two” as the number of categories the human mind can grasp as an intuitive whole. Zero to five is nearly as good, except that with an even number of categories, it doesn’t provide a “neutral” response, and I kind of want to think of there being a neutral response from which other responses depart. Zero to ten seems like too many categories for all of them to be intuitively meaningful.

Equality ratings as such don’t do anything for me; I have no intuitive sense that inequality is objectionable, and my instinctive feeling is to regard people who complain about it as envious and therefore wicked. Pragmatically I’m inclined to see inequality as a power source in economic dynamics just as it is in thermodynamics. Now I would rather that inequalities not be frozen in place and impossible to change, but I tend to believe that if you adopt a system of “natural liberty” (to put it in Smithian terms) you severely hinder any attempts to freeze inequalities, and get closer to “shirtsleeves to shirtsleeves in three generations.” Given this, I wouldn’t incline to make much use of an equality index as such, though I might be interested in an index that was correlated with inequality, if it told me something I cared about more. (I could believe, for example, that extremes of either equality or inequality are likely to involve a repressive political system.)


However little one might object to inequality as such (and like you, I am not troubled by the wealth of the rich provided that the poor are not in misery), it still makes a qualitative difference whether the community is financially diverse or not. Ought one to describe the cities having gilded towers? Is there a spreading apron of cardboard shanties around the urban core? Can the PCs lose themselves in the stews of the waterfront? Or is the typical city a scabrous blight of terracotta-roofed subtopia from the mountains to the sea, like Sydney in the Fifties.

It’s a dimension of information that GMs and character-players might want to have and use in about every colony, and so I try to jam it succinctly onto the summary sheet.

I like 0-6 because it fits the cognitive psychologists’ idea of “the magical number seven, plus or minus two” as the number of categories the human mind can grasp as an intuitive whole. Zero to five is nearly as good, except that with an even number of categories, it doesn’t provide a “neutral” response, and I kind of want to think of there being a neutral response from which other responses depart. Zero to ten seems like too many categories for all of them to be intuitively meaningful.

Fair enough: I guess we see that in (for example) the Kinsey scale, and not just in GURPS.

Now which works betteron a scale 0–6? Equality or inequality?


Do positive and negative skewness produce symmetrical effects on the Gini index?


Sometimes that’s arbitrary. For example, in the Big Five personality scale—OCEAN, for Openness to Experience, Conscientiousness, Extraversion, Agreeableness, Neuroticism—the last variable can be called either “Neuroticism” or “Emotional Stability,” depending on which direction you want to count as positive. Do you want to say that the positive trait is Equality or Stratification?

I was thinking about how you might make it correspond to the Control Rating system, but I think actually it can work either way. Stipulating that ER stands for Equality Rating, we can have

CR 0, ER 0: Some one person has all the wealth and does whatever they like, but it can change at any time if someone comes along and takes it away
CR 0, ER 6: Everybody has equal wealth, and it’s kept equal by mob violence against anyone who sticks out
CR 6, ER 0: Classical tyranny
CR 6, ER 6: Dystopian socialism, or Rousseau’s General Will


I’m not certain, but I don’t think so. It is a pretty horrible statistic, mathematically.


While I probably wouldn’t start with equality, I do think it would be nice to have more game-mechanical support for the GM to answer the question “we’ve just arrived on this planet, what’s it like”. CR is obviously biased towards the American obsession with firearms; I wonder whether extending CR to deal with more interesting things, in the spirit of “the law is a thing that stops PCs taking the easy option”, might also be a workable approach.


Another area in which GURPS’ definitions of CR nails a distinctive set of colours to the mast is when it treats taxes as a burden with little regard for whether they are spent on free medical care or hauled off to Blighty by the HEIC.


I wonder whether “shames” would be a better heading than “taboos” for what I have in mind there.


GURPS does recognize precisely the distinction you’re pointing to. A society that spends tax money on largely things that are arguably beneficial is CR2 or 3; one that spends it abusively is CR 5 or 6. See for example p. B506, which says of CR3 that “Taxes are moderate and fair” and of CR5 that “Taxation is heavy and often unfair.”

And in practice, every political system you can expect to encounter in the real world has CR2-6. The only example for CR0 is the hypothetical case of anarchy, and there is no example for CR1.

But logically, “the state takes none of your money/income/wealth” does seem to be at the other end from “the state leaves you only bare subsistence, or perhaps not even that,” in the same way that “everyone has the same income/wealth” is at the other end from “one person has as close as possible to all the wealth.” The CR continuum includes purely abstract, hypothetical cases, just as the Gini index does. That’s why I think it’s a good parallel.

Of course, I do basically think that taxes are a burden, and that Mancur Olson’s “stationary bandit” model of the state is essentially sound (see also James C. Scott’s The Art of Not Being Governed). That probably makes me sensitive to the need for a language that CAN express my point of view, rather than one that simply excludes it as inconceivable. But I think that the considerations above are sound independent of my fairly hard core libertarianism.


The thing that that CR model of taxes seems to exclude is the mode in which the state takes almost every output from economic activity… but genuinely does manage to provide for everyone’s needs. Call it a socialist utopia, if you like. I find the extreme case about as unlikely as an anarchy that doesn’t turn into warlordism, but I see no reason why it shouldn’t be supported.


If you follow Agemegos’s point about including goods and services provided by the state in “wealth” or “income,” then I don’t think that counts as confiscatory taxation, at any rate. It might be argued that it’s CR 3, in that people pay taxes, but they get goods and services back, so their net income is not radically decreased and may even be increased (if you believe in the efficiency of socialist institutions, which I don’t, but this is a utopia and that’s its premise). Or if you have an inefficient and wasteful but still somewhat functional socialism, it’s maybe CR4.

Though I have to say that it’s a question of your ethical judgments. By my standards, taking assets from person A, under force of law, to provide benefits to person B is by definition unfair; as Pratchett put it, it’s “a sophisticated way of demanding money with menaces.” Person A could perfectly well give money to person B (I have done so), or join in an actuarially fair insurance scheme with person B, or enter into various other voluntary arrangements. But if you have other ethical views, you will likely disagree. But I’m not sure how one would formulate a set of options that don’t include any ethical premises. If you have any suggestions, have at it.


Whether it’s fair is a different question. I don’t think that CR or whatever ought to conflate fairness in with its other dimensions.

My point was not that GURPS treats all taxes as unfair, but that it treats all taxes as burdensome. I believe that there are some types of goods and services (e.g. defences, courts, police, transport infrastructure, medical care, dentistry) that relieve burdens that are placed on human existence by our competing to flourish in a limited environment with frail and mortal bodies subject to injury and disease. For various reasons (assorted market failures) some of these services cannot be provided commercially, or the forms and quantities of them that result from commercial provision are defective, inadequate, or allocated with gross inefficiency. And in some of those cases tax-funded public provision of those goods and services is much better and also cheaper than the commercial provision. To me it seems nonsensical to describe the taxes that fund effective police and efficient courts as a burden. The feasible alternatives are far worse. Raising a tax and spending it on effective police and efficient courts is the opposite of a burden. It makes everything lighter than in any possible alternative.

Paying taxes, even progressive taxes, to maintain the systems that allow you the peaceful and secure accumulation of wealth, does not seem to me to be a burden when the feasible alternative is either paying more for less peace, order, and good government or living in a Hobbesian bellum omnia in which such an accumulation is not even possible. The fantasy world in which you get to earn the income and accumulate the capital of an industrial magnate without paying taxes is infeasible, and therefore not a valid basis for comparison.

Now, whether roads, defence, and socialised medical care are examples of such goods and services is a matter of fact and circumstances, to be addressed with evidence. And, I submit, beyond the scope both of this thread and this board (we can take it in private, if you like).

I feel the force of your argument that a GURPS CR or a Flat Black planet summary sheet ought to be able to describe a society which is contentiously realistic or unrealistic, even one that is uncontroversially unrealistic! Yes, there ought to be a code for an idealistic anarchy that does not collapse at once into banditry. For the same reason, it should not be impossible to describe a situation in which the government levies large taxes and spends them beneficially. I’m not saying that that is fair or even realistic, I’m saying that there ought to be a CR for it. That is, the issue of whether tax revenues are well-spent ought not to be included in CR.