Trade Missions - Let's get the facts on the table!

[krikav]

In a other thread, the topic of trade missions were frequently mentioned. But it seems that the majority of people (including myself) only have some pieces of the total picture,

I suspect that we could benefit from a arena to discuss this part of the game, to make better use of our Great Merchants.


What makes a city a good candidate for a trade mission?

Capital?
Costal?
Size?
Does sharing a religion make any differance?
Temple of Aretmetis, what does that do?

And probably many more!
Let loose the theorycrafting hounds!

 

[krikav]

The distance of the target city does seem to affect the result of the trade mission.

But the distance from what accually?
Is it the distance from the city that the Great Merchant spawned in?
Is it tthe distance from my capital?
Or perhaps the distance from my closest city?

 

[vicawoo]

Another continent is obviously more, as is the Temple of Artemis.

But it turns out hitting a capital (at least early game) doesn't provide more gold. Unless it's a very large continent, early on I just hit the closest AI city as long as there's no Temple of Artemis.

 

[Kid R]

Just quickly looking at the code the distance to the target city and the target city's size both come into it but it looks like only one or the other. It does a little bit of calculation and then seems to take whichever's the smaller of the two resulting values, so it would seem far away or large is fine but the farther you go the larger the city has to be for it to be worth going that far. E.g. a tiny far city will presumably yield the same as a tiny near city. Only after that value's been decided does it incorporate all the trade modifiers like peace, overseas, our city size etc.

I'll pick through it a bit more later on but a bit rushed this morning

Edit:

Is it the distance from the city that the Great Merchant spawned in?
Is it tthe distance from my capital?

From capital.

 

[Knightly_]

^ what kid_r said. It calculates with the traderoute value your capital would get from the target city. There things like city size, distance, oversea, years of sustained peace have an effect. Often you want to use the Tempel of Artemis city because that gives another +100% multiplier. The trade mission is then something like 500+200*(traderoutevalue) where i dont know the exact values....

Knightly_

 

[coanda]

Trade mission formula:
http://forums.civfanatics.com/showthread.php?t=318189
[500 + 200*(trade route yield)] * Game Speed multiplier, where the yield is the commerce the owner of that city would get from a trade route between that city and your capital.

Trade route formula:
http://www.civfanatics.com/civ4/strategy/trade_routes.php

Pick large, distant cities. You want them to be intercontinental if possible. Coastal is good - for the Harbor and/or Custom House bonus - and if you can figure out where ToA was built, that's another plus.

 

[Keilah]

I don't know exactly but doesn't it just check the traderoute value (from your capital to the target city I assume), then multiply by ?something? to get an amount?

 

[krikav]

Just quickly looking at the code the distance to the target city and the target city's size both come into it but it looks like only one or the other. It does a little bit of calculation and then seems to take whichever's the smaller of the two resulting values, so it would seem far away or large is fine but the farther you go the larger the city has to be for it to be worth going that far. E.g. a tiny far city will presumably yield the same as a tiny near city. Only after that value's been decided does it incorporate all the trade modifiers like peace, overseas, our city size etc.

I'll pick through it a bit more later on but a bit rushed this morning

Edit:

From capital.

Okay, you seem to say that what you get from the trade mission is determined in this manner:

TradeMissionYield = BaseTradeMissionYield + MIN(BonusYieldFromDistance, BonusYieldFromSize);

Sounds like something that would be very hard, to give general guidelines about, in a standard game.
But a general guideline might be "try to find both a somewhat distant city, that is also somewhat large.".

 

[krikav]

I don't know exactly but doesn't it just check the traderoute value (from your capital to the target city I assume), then multiply by ?something? to get an amount?

This might very well be the case. A larger more distant city does have higher traderoute value.

So the largeness of the city, and distance of the city, might not effect the trade mission direcly, but rather indirecly.

Largeness of city effects traderoute yield which in turn effects trade mission yield.

 

[krikav]

Trade mission formula:
http://forums.civfanatics.com/showthread.php?t=318189
[500 + 200*(trade route yield)] * Game Speed multiplier, where the yield is the commerce the owner of that city would get from a trade route between that city and your capital.

Trade route formula:
http://www.civfanatics.com/civ4/strategy/trade_routes.php

Pick large, distant cities. You want them to be intercontinental if possible. Coastal is good - for the Harbor and/or Custom House bonus - and if you can figure out where ToA was built, that's another plus.

This seem to indicate that it is the trade route yield that is the most important factor when determining a trade mission yield.

Regarding ToA, then it shouldn't matter if you choose the city in which ToA is built, but the important thing is rather to choose a city that belongs to the civ, that has built ToA ?

<edit> Does ToA only effect the city in which it is built? Like National Epic does? I previosly belived that it effected all cities, like the Partheron. </edit>

 

[Keilah]

ToA affects only the city it is built in. It will effectively add +1c to each trade route for a long time, until a city is so large + distant that the base trade value is >2c.

 

[kossin]

Use the shift trick if you aren't certain.

http://forums.civfanatics.com/showpost.php?p=9576182&postcount=202

 

[Higher Game]

The fact is, trade missions are almost always better than scientist bulbs. Scientists are usually just for people who absolutely can't stand to just let go of the whip. Probably by engineering and definitely by guilds, it's time to let go and start using caste merchants.

Well, philosophical guys might get away with just market merchants.

 

[oranje willem]

The fact is, trade missions are almost always better than scientist bulbs. Scientists are usually just for people who absolutely can't stand to just let go of the whip. Probably by engineering and definitely by guilds, it's time to let go and start using caste merchants.

Well, philosophical guys might get away with just market merchants.

Your better off skipping guilds/engineering and use scientists to win liberalism, after liberalism GM are indeed better than GS, but before? I strongly doubt it + they are a lot harder to get early on.

 

[krikav]

Just quickly looking at the code the distance to the target city and the target city's size both come into it but it looks like only one or the other. It does a little bit of calculation and then seems to take whichever's the smaller of the two resulting values, so it would seem far away or large is fine but the farther you go the larger the city has to be for it to be worth going that far. E.g. a tiny far city will presumably yield the same as a tiny near city. Only after that value's been decided does it incorporate all the trade modifiers like peace, overseas, our city size etc.

I'll pick through it a bit more later on but a bit rushed this morning

Edit:



From capital.

Perhaps it would be a good idea to simply look in ones own capital, to find the highest yielding trade route?

 

[goldys_lackey]

Use the shift trick if you aren't certain.

http://forums.civfanatics.com/showpost.php?p=9576182&postcount=202

Great tips!

I was the one in the gold/research thread who suggested religious shrines increase trade mission yield. I think the "Temple" part of ToA confused me. Temple, shrine, cathedral... I'll sort them out one of these days.

 

[ecuwins]

Use the shift trick if you aren't certain.

http://forums.civfanatics.com/showpost.php?p=9576182&postcount=202

That is the deal right there.

 

[Celebithil]

The value of a trade route from A->B has only smallish correlation with the value of the trade route B->A. The shift trick will of course always work (and with some calculations reveals whether other cities have harbors and such ;-)) but to know which cities to check it helps to know which cities have a high trade route yield to your capital.

Since you can't change the size of your capital, the base yield of the trade route is of the form min(distance to your capital, some constant depending on your capital size). This means that the value increases quickly with distance from your capital and is constant for all cities further away than some given distance. Thus, as long as the target city is not too close to your capital, the base yield does not depend on distance to your capital.

Thus, if we exclude the cities really close to your capital (with non-maximal base yield), the yield of a trade route only depends on the bonus modifiers. The big ones there are
- sustained peace with yourself (150%)
- intercontinental (100%)
- buildings: Temple of Artemis (100%), Custom House (100%), Harbor (50%)

Small bonuses are given from
- Size of target city (5% for each pop above 10, so not very relevant, but still somewhat noticeable)
- Connection to their capital (25%).

Thus you should focus on intercontinental cities from peaceful neighbors, with ToA (if possible), or otherwise coastal (otherwise there is no harbor or custom house) cities. The size of the target city plays only a minor role. The only reason foreign capitals do well as targets is that they tend to be larger (small bonuses do help) and more developed (=more chance of a harbor).

 

[Handel]

BTS, Marathon: My merchant could do 5700 golds in a coastal city on another continent but I moved it to the capital which was much bigger, farther and inland - for 5100 golds
Moved then to another big inland city - 5100 golds again.
So at least at BTS it seems the coastal cities have some advantage.

 

[coanda]

you can't change the size of your capital

But you can change your capital! Heck, it'd probably be worthwhile if you were in State Property and not in Bureaucracy to deliberately move your palace to a remote GP farm just for trade mission gold. 160 hammers to move it; if you can boost base trade route yield by just 0.5, you might well get 500 or more out of it.