Part 21: Habitable Area and You: A guide to Maximum Population (and Food) On Planets (Olesh)Habitable Area and You: A guide to Maximum Population (and Food) On Planets
There are two base factors that determine exactly how much population you can fit on a planet - it's size and its habitable area. We'll start with size, because it's simplest.
Planet size is displayed as a descriptive text. In order from smallest to largest, these are Tiny, Small, Medium, Large, and Huge. Mathematically, you can describe the planets as Size 1 through 5, with 1 being a Tiny planet and 5 being a Huge planet. The maximum population (100% habitable area) of a planet of Size N is equal to 5 * N, so under normal circumstances a Tiny planet caps out at 5 population and a Huge planet caps out at 25.
However, normally you don't get to benefit from 100% of the habitable area of a planet. The available habitable area of a planet is restricted by the planet's biome.
There are ten habitable biomes in the game - Toxic, Radiated, Barren, Desert, Tundra, Ocean, Swamp, Arid, Terran, and Gaia.
Under normal circumstances, only Gaia planets have 100% habitability.
Terran planets provide 80% habitability, Arid planets allow 60%, Swamp planets provide 40%, and all other planets only provide 25% habitability.
In addition to its habitability, each biome also features a base of between 0 and 3 food per worker. However, racial picks (such as +1 Food) don't allow you to grow food on a 0 food biome, so keep that in mind.
Toxic, Radiated, and Barren planets are 0 food biomes.
Desert, Arid, and Tundra planets are 1 food biomes.
Swamp, Ocean, and Terran planets are 2 food biomes
Gaia is the only 3 food biome.
Now, Thotimx is playing an Aquatic race. This means that his race treats Tundra and Swamp planets as if they were Terran, and Terran and Ocean planets as if they were Gaia. Let's break down what this means for those specific planets:
1 food -> 2 food
25% habitability -> 80% habitability
2 food -> 2 food (no bonus here!)
40% habitability -> 80% habitability
2 food -> 3 food
25% habitability -> 100% habitability
2 food -> 3 food
80% habitability -> 100% habitability
As you can see, Aquatic is situational, but pretty strong! Two planets that are normally poor colonization options (Tundra and Ocean) get fantastic upgrades, to the tune of +1 food and 3/4 times as much maximum population space out the gate. Swamps get upgraded with double the habitable area (but no extra food), and Terran planets, already a good pick, get +1 food and 25% more max population. It can be a little bit of a gamble, since there's no guarantee that you'll find any planets that allow you to benefit, but considering that the "+1 Food" racial pick is 4 points, Aquatic gives you all that and more for only one more point and a little luck on planet availability, if you're willing to freight food around.
There's two other racial picks to discuss here, and we'll start with Tolerant.
Tolerant is a 10 cost genetic pick. It eliminates the pollution penalty for production and also claims to increase the maximum population of all colonies by 25%. This is mostly accurate, but misleading.
What Tolerant actually does is provide a flat +25% bonus to the habitability of each biome, up to a maximum of 100%. This means that bad habitability biomes that normally only have 25% habitability, instead provide 50%. Swamps go up to 65% habitability, Arid planets provide 85% habitability, and Terran planets cap at 100%. For Gaia planets, of course, Tolerant can't increase the habitability beyond 100%, so it does nothing beyond eliminating the pollution penalty.
Then, we have Subterranean. A 6 point genetic pick, Subterranean gives all your colonies a 10% ground combat bonus when defending a colony, but more importantly it also gives a flat 40% bonus to the habitability of all biomes. Unlike Tolerant, Subterranean does not cap habitability at 100%, meaning that for all intents and purposes, Subterranean gives you an extra 2 population per size class on every planet. This means that the shittiest Tiny planet still supports a minimum of 3 population, and the worst Huge planets support 16 - as many as a normal race could support on a Large Terran world.
These modifiers can be stacked, of course. You can't normally have an Aquatic Tolerant Subterranean race because that's 21 picks, too many to get without shenanigans.
Lastly, any colony upgrades or researches that apply increases to the maximum population of a colony apply at the very end - Biospheres will always increase max population by 2, and Advanced City Planning will always increase maximum population by 5.