Planetary populations

Of the 500 planets in the Echo Cluster, many are inhabited by natives. Additionally, you and the other players will work as hard as you can at colonizing the planets with your own clans. Usually, both native and colonist populations grow each turn. However, the Climate Death Rate (CDR) usually limits the amount of natives or colonist a planet can inhibit. At some point, the population stops growing and usually the colonist overpopulation will even die.

Population growth
On each planet that is colonized by one of the eleven races, the native population may grow, if the climate allows it. Native populations on unowned planets do not grow. Colonist populations also grow, if the planet's climate allows it. Population growth for natives and colonists follow different formulas, and then there are different formulas for Siliconoid natives and Crystalline colonists.

Native growth
Native populations grow each turn a planet is owned by someone, but growth is influenced and limited by a number of factors. Because of growth, a number of clans is added to the native population as long as two criteria are met:

• Happiness must be at 70 points or higher, including the effect of taxes imposed in the current turn. If happiness is currently below 70 but will rise to 70 or more points because of low (or no) taxing in the current turn, growth will occur. If taxing in the current turn will cause happiness to drop below 70 there will be no growth.
• The Growth limit (depending on the planet's temperature) may not be reached yet before the clans are added.

The Growth limit, often referred to as maximum population, is in the case of native populations not a hardline limit to the size of the population, but a limit above which there will be no more growth. A population that is just one clan smaller than the "maximum population" will have normal growth, likely bringing the population to exceed the Growth limit. From the next turn on there will be no more growth.

If for some reason (civil wars, meteor-impacts) the population drops below "maximum population" again, growth will occur by the same rules. If a number of natives die but the population stays above "maximum population" there will be no new growth.

Generally speaking, a native population will grow at 5% per month if the conditions are perfect. Perfect conditions mean no taxes and a good climate (50 for all races except the Silliconoids who prefer 100). Temperatures differing from the preferred climate impact growt in a negative way, as ofcourse do taxes.

The population growth formulas for all native species but Siliconoids are:
Clans added = ROUND[ SIN(3.14*((100-temperature)/100)) * (native clans/25) * (5/(taxrate+5)) ]
Growth limit  = SIN(3.14 * ( (100-temperature) / 100)) * 150000

"Clans added" is the growth of the population, which is measured in clans. When a population is at or above the "Growth limit" it will not grow.

Siliconoid natives like hot planets, and have their best growth rates on those planets. The formulas for Siliconoid natives:
Clans added = ROUND [(temperature/100) * (native clans/25) * (5/(taxlevel+5)]
Growth limit = temperature * 1000

The number of native clans added is rounded (not truncated, as in many of Tim's formulas)
Large populations grow slower than small populations: once a population exceeds 66,000 clans (6.6 million), the growthrate is halved - for all natives, the amount of clans added gets halved if before growth there are already more than 66000 clans.

Colonist growth
Colonist populations follow different rules and formulas when it comes to growth. They do not grow when:

• The temperature of the planet is below 15 degrees (Arctic planets)
• The temperature of the planet is above 84 degrees (Desert planets)
  (this rule does not apply to Crystalline colonists, they actually love high temperatures)
• Colonist happiness is below 70 points or will drop below 70 points because of taxing in the current turn
• The Growth Limit is reached, based on the planet's temperature.

The growth limit for most colonist populations: Growth Limit = SIN(3.14*( (100-temperature) / 100) ) * 100000

For Crystalline players with the "Crystal desert advantage" Hconfig option set to Yes, the maximum population / growth limit is 1000*Temperature.

Under perfect conditions, a colonist population will grow at 4% per month. Perfect conditions mean the preferred temperature (50 for all races except the Crystalline who generally like 100 degrees, assuming 'crystal desert advantage' is set to it's default of YES in the host configuration) and ofcourse no taxes. Temperatures deviating from the preferred temperature and taxation are bad influences on growth.

As long as none of these criteria are met,  a number of clans are added to the population by the following formula:
Clans added = ROUND [SIN(3.14*((100-temperature)/100)) * (colonist clans/20) * (5/(taxlevel+5)]

Crystalline colonists follow a different formula when the host-option "Crystals like deserts" is set to YES:
Clans added = ROUND [(temperature/100) * (colonist clans/20) * (5/(taxlevel+5)]

The number of colonist clans added is rounded (not truncated, as in many of Tim's formulas).
For all races, the amount of clans added gets halved if before growth there are already more than 66000 clans.

The absolute maximum colonist population when the Hconfig option "Climate limits population" is set to No is 10,000,000 colonists (100,000 clans).

Population limits

Natives
Although a native population will not grow larger than it's growth limit, Native populations can have a size greater than this growth limit would suggest. The growth limit is not more than that: the number above which there will be no more growth. Native "overpopulations" won't die or eat supplies because of climate restrictions.

The growth limit for most native populations: Growth limit  = SIN(3.14 * ( (100-temperature) / 100)) * 150000
Silliconoid natives have a more linear limit: Growth limit = temperature * 1000

Colonists
When it comes to colonist populations, there are two options. On hot and cold planets -with temperatures above 84 or below 15 degrees- the maximum number of colonists is determined by several mechanisms and rules. On all other planets, there is just a plain formula to calculate the maximum population.

"Normal" planets
For planets where the temperature does not prevent growth, the maximum population for all colonists except the Crystals works rather simply:

Maximum population = SIN(3.14 * ( (100 - temperature) / 100) ) * 100000.

Crystalline colonists follow a different formula when the "Crystal desert advantage" is set to YES. Quite simply, with that setting Crystals can support 1000 clans (100,000 colonists) per degree:
Maximum population = 1000 * temperature.

Any colonists exceeding the maximum population will die, without any message or distress call to tell you.

Hot and cold planets: the Climate Death Rate
For planets hotter than 84 or colder than 15, special rules apply to the maximum population and which part of the overpopulations will die. The Climate Death Rate (CDR) is used to calculate which portion of the present clans will be labeled 'overpopulation'.

The absolute maximum amount of clans a desert or arctic planet can support (if 'overpopulation eats supplies' is not enabled), can be calculated using these formulas:

• Arctic: Abs.maxpop = TRUNC [ (299,9 + 200 * temp) / CDR]
• Desert: Abs.maxpop = TRUNC [ (20099,9-200 * temp) / CDR]

Exceptions to these formulas:

• Rebels can have up to 90,000 clans (9 million colonists) on any planet with a temperature of 19 degrees or less.
• Fascists, Robots, Rebels and The Colonies of Man can support a small outpost of 60 clans (6,000 colonists) on planets with temperatures higher than 80 degrees. The online documents and the Winplan helpfile are incomplete at this point, as only the Fascists and Robots are documented to have this advantage.
• Crystalline colonists follow a completely different formula when "Crystal desert advantage" is set to YES.
  Quite simply, with that setting Crystals can support 1000 clans (100,000 colonists) per degree:
  Abs.maxpop = 1000 * temperature.
  This indeed means the Crystals can not have any clans on planets where the temperature is 0 (zero).

A hot or cold planet can have more colonists on it than would be allowed by these formulas, but as long as the population is greater than this maximum, each turn a part of the population will die. This continues until the population has decreased to the absolute maximum that is allowed based on the planet's temperature.

Each turn as long as the population is greater than the maximum population, the 'overpopulation' in that turn either dies or eats supplies to survive.

(The mechanism to calculate how many clans die -or rather survive- each turn is on the details page.)

Overpopulation eats supplies
If a planet's colonist population exceeds the maximum population and the Hconfig option "overpopulations eat supplies" is set to Yes, a number of colonists greater than this maximum can stay alive by eating supplies available on the planet.

Cutting a rather long and complicated story short: effectively, every forty supply units present on the planet can sustain 100/CDR clans. At the default CDR of 10%, forty supply-units can thus sustain 10 clans above the 'absolute maximum population'. To sustain a population of 800 clans above the absolute maximum population you'd need 40*800/(100/10) = 40*80 = 3200 supply-units present on the planet to survive. Oddly, these 800 clans would only really "eat" three supply-units to survive.

(The mechanics and formulas used to calculate how many can survive per turn are explained on the details page.)

Overpopulation dies
Each turn, host calculates the "current maximum population", either through the regular formula or via the overpopulation eats supplies formulas, depending on the hostconfiguration. The planet's population is then checked against this number. If at this point the planet is found to be overpopulated (number of colonist clans is greater than this current value for the maximum population) the entire overpopulation dies.

Though this might seem to contradict popular belief that only a percentage (related to the Climate Death Rate) dies, it does not. Rather than regarding the CDR in the amount of dying overpopulation, the CDR is used to re-establish the current maximum population (based on the current number of clans) each turn until a stable situation is reached.