how is the GM trade mission revenue calculated?

Does anyone know how the revenue for trade missions is calculated?

In my current game I am playing as Japan in Rhye's and Fall of Civilization. My first Great Person was a Merchant and I sent him on a merry trip to Europe. He appeared there just as France spawned, but after arriving in Paris, the trade mission revenue turned out to be a meagre 900 gold. I don't know whether it's better to grab the money now or to wait some time for a juicier reward.

Ok

The gold is given based on things that modify a trade routes yield, these are:-
-City population
-Distance
-Overseas (this is pretty big especially early on and are very strong on archipelago maps)
-Harbours and probably customs houses
-Temple of Artemis being in the city and not obsolete
-Unsure if the being a capital makes any difference though

The presence of anything (in the city your using the mission in) that improves trade route yield % increases the trade mission value.

The number of trade routes does nothing (i.e. Great Lighthouse dones't help)

If the civ who owns the city your using the trade mission on is using the Mercantilism civic, then the trade mission always gives the same very low flat amount of gold. Avoid mercantilist civs at all cost with GMs
For your case, check if France is using Mercantilism (Likely as its 800 AD although why are you only now teching currency!? A mod?)
If so go to a civ who isn't using Merc.

and plus never go to cities that are pop 3, not even if theyre a million miles away. if you had been more patient you couldve sat on paris till it hit 12-14 (which it can do quickly since its such nice land) and hit the jackpot!

Thanks for the replies. I only knew that distance and population matter, but I wasn't sure how much they matter or if anything else contributes. I also for some reason assumed that the era in which the GM is used is quite important, but I geuss now that it isn't.

I tried searching and was a bit surprised that I couldn't find a mathematical explanation on how trade mission revenue is calculated on this forum (seeing how almost every mechanism in CIV has been somehow explained). Oh well, not everything in CIV must be governed by cold logic.

ok, some cold logic (though idk about peculiarities of RFC):

The formula for the revenue of a trade mission conducted by your GM in a target city is:

Profit = (500 + 200 * CapitalTradeProfit) * GameSpeedMultiplier

500 = iBaseTrade, 200 = iTradeMultiplier for the GM (from CIV4UnitInfos.xml)
GameSpeedMultiplier = the usual 0.67 | 1.0 | 1.5 | 3.0 for Quick | Normal | Epic | Marathon (iUnitTradePercent/100 from CIV4GameSpeedInfo.xml)

CapitalTradeProfit is the income the target city would get for a hypothetical trade route to your capital. It is irrelevant if the owner of the target city has met all necessary requirements to enable a real trade route --> Mercantilism has no effect (see example below). All modifiers are factored in (Harbor, ToA, TargetCitySize, ConnectionToCapital, Overseas, Foreign, PeaceTime). Thus the ToA-city is often optimal, but not if it is an inland city close to your capital on the same landmass. Since the Base Profit of a trade route is Max(1, Min(SizeOfOtherCity, PlotDistance)/10) you should always attempt to have a big capital (wait for growth before starting missions).

Example:

My GM is in Cuzco, Huyana Capac is currently in Mercantilism plus he doesn't have Astro yet (necessary for intercontinental trade to my capital), thus he doesn't have / cannot establish a real trade route. Still the GM's trade mission will yield the nice sum of 4950 (epic speed)!



After giving him Astro and forcing him into Free Market, Bibricate (my capital) shows up as the top trade route in Cuzco's city screen.
Hovering the mouse over the 14 reveals:

• Bibricate is size 22 and far away enough --> Base profit = 22/10 = 2.2
• Harbor +50%, ToA +100%, Overseas +100% all clear
• Population +30% --> Modifier for TargetCitySize = +5% for each population point above size 10, Cuzco is at size 16 --> 6*5 = +30%
• ConnectionToCapital +25% --> Cuzco is connected to Huayna's capital Cuzco
• Foreign +100% --> Cuzco has a Customs House
• PeaceTime +150% --> +3% for each turn at peace (max 50 turns)

Total Modifiers +555% --> Trade route yield = floor(2.2*6.55) = 14

Profit = (500 + 200 * 14) * 1.5 = 4950

I'm not sure about RFC, but your comment that France just spawned lets me assume, that you could not accumulate any percentages for the PeaceTime modifier yet, so you only benefit from the Overseas +100% while your capital is still <= size 10. (Or did you move your palace to the main land?) Inland Paris would only get 2 for a hypothetical trade route to Kyoto --> Profit = (500 + 200 * 2) * 1.0 = 900 .

Thanks a lot. I could never figure out how that worked. The discription for the GM makes it confusing as to how the trade mission works. I had Paris grow from pop 3 to 8 and nothing changed. The capital trade profit system on the other hand really seems perfect in its simplicity.