New GM question

[dutch206]

OK. Getting in to Traveller for the first time. I have a fractal planet generator, so I am not worried about planet generation. What concerns me is the next step. How do I decide how many cities a world has for a given population code?

For example, a world with a population of "tens of billions" is going to have a LOT of cities. The questions are: Where? How far apart? How do I decide how many people live in each city?

This may seem like nit-picking, but I think it is important stuff to know. It makes a difference in how the world is described and how it feels.

Any help would be appreciated. :mrgreen:

 

[Jeraa]

However many you want it to have. There are no guidelines.

And just remember, that population doesn't have to be all on the planet. If the tech level is high enough, orbital habitats and (possibly) moon bases could be included in that population as well.

And you need to define what a "city" is. There is no set definition. What qualifies as a "town" in one area may be a "city" in another. Or the other way round.

New York City has a population of over 8 million. Shanghi, China has 18 million. But I live in the city of Franklin, Indiana. We only have a population of roughly 23,000. Before that, I lived in the city of Bedford, Indiana, with only 13,000 people.

Since you can't give a definite answer "How many people in a city?" as the population of cities varies by a huge amount (from 10 thousand to 10s of millions), you can't answer "How many cities on a planet?"

 

[Galadrion]

Also remember that a system/planet with a higher population code is (probably) going to have larger cities.

In general, it's highly unlikely that the planet's largest city is going to have the same population code as the planet itself - a planet with billions of inhabitants (such as present-day Earth, for example) is unlikely to have any single city with over a billion inhabitants, even if the planet itself is approaching the next pop code in size. Remember, that's going to mean that more than one out of every ten inhabitants lives in that one city.

One size code down is more likely, but still iffy. At this point, using Earth as an example, you'd be talking about cities with populations in the hundreds of millions. Officially, we ain't got any. Still, it's possible - but you're probably not going to have any more than about twenty to thirty of them, and then only if there's some good reason. More likely you're going to have less than ten of these.

Two size codes down - this is the situation modern-day Earth is in. Tokyo is the most populous single city, weighing in at about 32.5 million, or a little less than half a percent of the global population. There are currently 23 cities on Earth which qualify for a Pop code of 8, 24 if you round up for Paris (at 9.6 million).

Each step down is going to have around eight to twelve times as many cities as the next larger level, unless there's something interfering. But honestly, most of the time your characters are not going to be hitting more than one to three cities on a given planet, unless it's part of your game plan. So think through what you want to happen, and set the scene accordingly. Just try to avoid the glaringly obvious mistakes, such as a city the size of New York on a planet with a Pop code of 7. As long as you come close to being reasonable, most players aren't going to be in any position to spot your mistakes, and they're more than likely to let the inconsequential ones pass anyway. (If you've got a player who just want to play "gotcha" games, you should probably be trying to get rid of that behavior/player and replace it with better.)

 

[locarno24]

It's also going to depend highly on the history and economy of the planet.

If a civilisation has grown up (or is growing up) on the world, it will be naturally dispersed. a <TL8 civilization - i.e. one that's been through the industrial age on the planet - will be spread out, with farming regions, industrial cities, population following rivers and coastlines where trade can occur - all the stuff you learned in secondary school geography.

By comparison, a world with a high TL (12+) may well be an established colony - created, regardless of its population, out of whole cloth with access to all the tech it currently has. Population dispersal will be highly dependent on why the colony was established.



Highly agricultural worlds will have a low (ish) population density, spreading out the population throughout the fertile regions, with regional cities for administration, civic facilities, etc.

Worlds with a dominant industry are likely to be centralised. Equally, some worlds will centralise around the starport. For a world which is essentially a trading stopover, you might have a city the size of London, Singapore or Rotterdam around startown and no other significant population on the planet.

 

[steelbrok]

And don't forget that planet size is independent of population

a size 2 world with a pop of 9 will be a lot more crowded than a size A world with the same population (differing hyd figures make this even more interesting)

In practice I like to take the Pop figure as a measure of how crowded a world is rather than worry about the absolute figures

 

[CosmicGamer]

Too many variables to give a (population = No. of cities) answer.

I take a look at the other attributes of the planet for clues. I think unbreathable atmosphere would cause people to live together in man made habitats. Even extremes of gravity could cause people to huddle together in locations where it is maintained with technology. Government types could be a clue: Balkanism vs a tightly controlled corporate run planet. Trade codes of agricultural vs Industrial. A high law level might restrict the populations ability to just "settle down" wherever they like or the opposite, it might cause people to go somewhere more remote where there is less enforcement.

 

[dutch206]

Thanks, all.

 

[Hans Rancke]

However many you want it to have. There are no guidelines.

I use the guidelines in World Builders Handbook.


Hans