Trade routes - how they working?

[Thunderbull]

Hi everyone!

I'm looking for info about trade routes - how do they work, how calculation working, how to uderstand is it profitable to make road to another city, etc.

Thanks for any info provided.

 

[Casper84]

As far as I've seen it's almost entirely related to the population of the city that is connected. I'll take another look when I play again though.

 

[delra]

It depends on POPs. There's little point connecting before they have 6-8 dudes inside.

 

[King Jason]

Here:

After digging around in the game data and doing some testing, I'm pretty comfortable with the way that trade routes between cities are calculated. I hope this will be helpful to everyone trying to decide when building a road between cities becomes profitable. The same calculation is used for all difficulty levels, but playing at anything below Prince reduces your route costs. See the modifiers section for more detail about this.

Revenue Calculation:
Trade route income is calculated based on the size of the city which is being connected to your capital's trade network. The size of your capital city is not currently used in the calculation and can be ignored when deciding to build a road or not.

Trade route yield is roughly equal to (Connected Non-capital City Size * 1.25). This appears to be true even when your capital city is smaller than your connected city.

For example, from one of my test games:
Kyoto(4) to Osaka(4):Trade Route Income 5.01
Kyoto(4) to Tokyo(5): Trade Route Income 6.26
Kyoto(4) to Satsuma(2):Trade Route Income 2.51

Roads:
Roads cost 1 gold per turn in upkeep...so if you need to build roads on ten tiles to connect your city to your trade network, you wouldn't break even from that expenditure until your connected city reaches size eight (8 * 1.25 = 10). Keep in mind that a longer road may still be profitable to build if it allows your trade network to be extended to multiple cities in another part of the map.

Harbors:
For remote cities, harbors may be a better investment than roads provided that at least one of your cities already within your capital's trade network also has a harbor to complete the link between cities. Harbors have an upkeep of three gold per turn. goodolarchie posted a cost analysis that compares the investment of buying a harbor outright with the number of turns needed to break even here.

Trade Route Modifiers:
I haven't tested all of the modifiers yet, but I'm listing the following based on the game data and/or documentation. Let me know if I'm missing something and I'll add it to the list.

Great Wonder - Machu Picchu: +20% more Gold from all Trade Routes. Must be built in a City within two tiles of a Mountain. Requires Currency.

Leader - Harun al-Rashid: Trade Caravan trait, +1 Gold from each Trade Route

Policy - Commerce/Trade Unions: Maintenance paid on Roads and Railroads reduced by 20%

Difficulty - Settler/Chieftrain/Warlord difficulty levels reduce road and railroad costs by 66/50/25 percent.

It depends on POPs. There's little point connecting before they have 6-8 dudes inside.

Not entirely true, depends on the length of the road, since roads increase the ease of movement between your cities which helps out your workers and your military, it can beneficial to get them up earlier and a city of about pop 4 will pay for pay for a road of about 5 hexes. If the cities are 4 tiles apart instead, you begin to turn a profit. Basically, I'd start connecting at pop 4. Unless your cities are far a part.

Fortunately, knowing the numbers allows you to make the decision on a city per city basis.

 

[PibbZ]

I really miss the detailed calculations... Give more numbers to crunch to make such decisions!

 

[alpaca]

I really miss the detailed calculations... Give more numbers to crunch to make such decisions!

To be honest the trade routes system in Civ4 was so complex it might as well have been a black box. There was no way to predict what will happen in an acceptable amount of time.

That said, I would have liked the Civ5 system to depend on the size of your capital, too. That would make centralized empires quite a bit more juicy.

One thing to add about harbors: They spread railroads.

 

[Rathelon]

I think the trade routes are kinda cool. In my current game, London is a non-coastal city and so is Nottingham, but all my other cities are coastal. So I built a road from London and Nottingham to York, then placed harbors in all the other cities - trade routes established with a couple short roads.

Of course, that makes it easy for the enemies to disrupt my trade network. But that's why I have a Ship of the Line guarding York.

 

[SolkaTruesilver]

That said, I would have liked the Civ5 system to depend on the size of your capital, too. That would make centralized empires quite a bit more juicy.

It would have been an interesting choice of civics: Trade system

- Capitalist (no control, pretty much like as we know it)
- Centralist (relative to size of capital and number of city)
- Node-based (trade regions that centers around "regional capitals")

 

[automator]

It depends on POPs. There's little point connecting before they have 6-8 dudes inside.

Only if you're running a very spread out empire.

Normally, I'll expand away to grab the nearest collection of luxury resources, I'll be building circuses/colluseums for some extra happy. And I'll notice my GPT has gone from +15ish to hovering +/- 2 GPT from zero ... so I'll start my road building. It usually works out that this is also when my workers are done building resource grabbing improvements. Yes, there is an initial dip in my GPT as unconnected roads are being built. But then that magic popping noise of a trade route connected starts happening, and I'm back to +15ish GPT!

Add to that the movement bonus of roads (try warring with no roads and let me know how frustrated you get), and roads are a clear winner.

 

[Pinstar]

Another reason to invest in maritime city-states; all that extra growth in cities increases your trade income. Since maritime city-states increase growth empire wide, thus they increase trade income empire wide (provided you have all cities connected).


Also one burning question: Does the commerce policy 20% boost to your capital's income have any impact on trade route income?

 

[Daniel D]

Also one burning question: Does the commerce policy 20% boost to your capital's income have any impact on trade route income?

The commerce capital city gold output boost does not impact trade route revenue.

 

[Zechnophobe]

It is definitely 1.25*size +.01. Why is there .01? I have no idea. This actually means that cities 3 tiles away are worth roading when they get size 2, assuming they'll be size 3 by the time you finish building. 3.75 vs 3 road cost. Size 3 is tiny.

Ultimately.. always build trade routes.

What I really miss is cutting people off from their resources by severing roads to their city. We can now cut their trade routes!... but that doesn't prevent them from getting iron from Alaska apparently.

 

[pi-r8]

The weird thing about this system is that in encourages you to keep your capital small, and use the happiness saved there to build up your other cities instead. I almost always build settlers in my capital now, and run scientists there too.

 

[neilkaz]

I think the trade routes are kinda cool. In my current game, London is a non-coastal city and so is Nottingham, but all my other cities are coastal. So I built a road from London and Nottingham to York, then placed harbors in all the other cities - trade routes established with a couple short roads.

Of course, that makes it easy for the enemies to disrupt my trade network. But that's why I have a Ship of the Line guarding York.

Prior to a week ago, I basically hadn't played Civ during this newish century. However, back in the day before I discovered the AOE RTS series of games, I almost always had a Civ2 game going (someone gave me Civ3 as a present but it sucked badly).

Anyhow.. re: Harbors .. My understanding is that they do nothing for trade if the city is allready connected to the capital by road. Harbors are for cities on other continents/islands.

Re: harbors again and with something important. In the mid/endgame of today's King level continents game as my beloved Askia (Songhai buttkicker) I had a map that had the default 6 civs broken up into 3 continents with two major civs each and there were CS spread around and occasionally on other islands. OK as we can realize this map is extremely favorable to a human with functionally brain cells since the AI is clueless with watery games and also each continents with two civs will results in them bashing each other and you can invade and kill the weakling while making "nice" to everyone else there who has likely been fighting them.

Re: harbors with the important fact I'll leave you with. I invaded the 2nd continent on a peninsula and with a settler to found a city in a nice spot (so I could, if things turned against me buy a couple units there) and have my beachhead. The AI had built roads all over so the builders I brought only needs to build roads on a few tiles to make it so that every city I was conquering was connected. I quickly purchased a harbor in my beachhead city and WTH... no trade routes ??? Finally once I razed the garbage cities after the capitols and good cites with lux, and my happiness was OK, the harbor I purchased didn't give my new continent trade until that city had pop 3 at which point my trade resulted in a wonderful increase in GTP.

OK.. re above..it seems harbors don't work UNTIL YOU HAVE POP OF 3 in the city with the harbor.

.. neilkaz ..

 

[weakciv]

Anyhow.. re: Harbors .. My understanding is that they do nothing for trade if the city is allready connected to the capital by road. Harbors are for cities on other continents/islands.

In my most recent game I checked out the strategic view and one of the Overlay options is to view trade routes. I found that a harbor was always used.

Something to keep in mind though is that your capital needs to be connected to the coast, whether by being built there or by roading to a city on the coast, for that harbor to connect the trade route. (this may not exactly be the case as I have never built a harbor in a city that my capital wasnt already "roaded" to a coastal city)

 

[the_lor]

Silly question (possibly), but do puppets operate under the same trade route profit conventions?

 

[madscientist]

Regarding trade routes in Civ V versus Civ IV.

Civ V is much easier (hell everything is easier) because it's a simple road to the capital that produces gold. The amount of gold depends on population of the connected city, the larger the population the more profit and subsequently the shorter the road to less upkeep. Special note to the Arabian Caravans which give you and extra gold (yippe!).

Civ IV was much more intricate as you could get multiple trade routes based on techs/civics. You had a base yield then modifiers based on buildings and diplomacy. There was also a difference between coastal and land-locked cities for trade route yield, which required consideration as you could lsoe prodcution with too many sea tiles. On top of this you only generated commerce which could be shifted to science/culture/gold/espionage. Not a black box but much more detailed than they appears.

To me, this is an example as how Civ V has been a little too simplified. There should be more diversity on what these trade routes do (building modifiers, open borders, oversea trade, etc...).

 

[alpaca]

The "black box" part refers to how the trade routes are calculated. Before building the city it's very hard to make an estimate about how much money you will get from that harbor because the trade route you get in this city may turn a trade route in another city less profitable, etc.

I agree it's not really a black box but I think most players saw it as such. Of course you get a feeling for how much you can expect after a while. I'm not arguing that the Civ5 system is preferable, mind, I also think it's a bit too simple. The main reason for removing the complex system is probably computation speed, though. In the late game and especially on large maps, the recalculation of trade routes could take seconds, which you can easily verify by blocking an AI's sea trade routes.

@puppets: Yes, they generate the same amount of money as a normal city.