Trade Routes

[Stickyman]

Can someone please describe to me how trade routes work?

I am playing a game where I am alone on a continent and using the merc civic. I am still able to trade with other civs.

How much gold is generated for each trade route?

If you have five cities in a hub a spoke set-up (all are connected to a center city, but not connected to each other), do all of the cities have five trade routes or just the center one?

Thank in advance for the help.

[Hauptman]

theres a few different versions of "trade routes"

the road network is just that, you hook up all your cities with roads or rivers and they all share resources.

Trade routes you get from currency, corporation, great lighthouse and airports just add "gold" to the city. thats in the upper left box in the city view. These are very important as larger cities with harbors can be making 12+ from each trade route. with up to 6 routes thats alot of extra research/ tech.

[Odin]

City trade routes simulate the income from domestic and international trade. trade can be between any two cities that can reach each other by road, river, sea, or any combination of the 3 (so an inland city on a continent, say, Minneapolis, can trade with an interior city on another continent, say Paris, if both are conected by road to a port city, or are on rivers that empty into the ocean).

[Jerh9e1k5]

I've been wondering how these work as well...

So if you have six cities and they are all connected each city will have six trade routes? Why do some trade routes give more money than other trade routes? What determines which city the trade route will be with? I can remember on more than one occasion having one of my own cities connected to all of the others in my empire, but having one single trade route to a friendly neighbours city. In this case why would the trade route be trading with the other civ rather than my fellow cities?

Thanks a lot,
Jerh9e1k5

[Caligula 37 AD]

Originally posted by Jerh9e1k5

So if you have six cities and they are all connected each city will have six trade routes?

Not quite so. The number of trade routes each city is entitled to is determined by the infrastructure of the city (i.e. Airports give +1), the civics you run (i.e. mercantilism+1), the wonders (Great Lighthouse gives +2 in coastal cities), the techs discovered (currency, corporation) etc. I think the maximum is 7 per coastal city with Great Light (8 with Mercantilism if you can have that before corporation which cancels Great Light)

Why do some trade routes give more money than other trade routes? What determines which city the trade route will be with?

The number of commerce from each trade route is determined by the greatness (not sure how this greatness is calculated) of both cities. Your best trade city will get the best trade routes, your second best, gets the next and so on. This maximises the total trade automatically.

Mostly the best trade routes are with foreign cities, but not always. Your best trade cities will therefore have foreign trade partners, while your crap cities are trading only internal.

There is no limit to how many trade routes a city can give within your own empire, so you will see many of your smaller cities trading with your capital.

However each foreign city trades only once to your whole empire. This limits the number of good trade routes. So if you have a large empire the marginal effect of trade in your newest city is small, as there are no new foreign cities available.

Likewise if you bulid an airport in a city (Washington), and the total trade for that city goes from 3*6cpt to 4*6cpt, it is likely that your nations total cpt does NOT increase by 6cpt, as the extra trade route in Washington only "steals" one foreign trade partner(Thebes) from one of your lesser cities (Seattle), and replaces it with an internal trade route giving for instance 2cpt in Seattle. Washington is the better trade partner, this could mean that Washington gets 6cpt from trading with Thebes, while Seattle only got 5ctp. The net increase for your nation in this case is +3cpt.

I can remember on more than one occasion having one of my own cities connected to all of the others in my empire, but having one single trade route to a friendly neighbour’s city. In this case why would the trade route be trading with the other civ rather than my fellow cities?

In these cases I suspect there was only one foreign city available for trade to your empire.
Remember trade routes in CIV4 only go one way, which is TO the receiving city. The city at the other end is not affected by the trade. This means foreign trade is nice, not bad.

For a foreign city to be available for trade to your empire, it has to be connected by roads/coast/rivers, as Odin stated in the previous post. Additionally you need an Open Border agreement with that nation.

One thing I have not figured out is how Free Trade works ("all foreign cities available").
1. Is the connection by roads/coast/rivers not needed?
2. Is the Open Border not needed?
3. Will foreign cities give more than one route to your empire? (not likely, that would be huge...)

[Jerh9e1k5]

Thanks for the great reply Caligula 37 AD!
That really clears that up for me.

Next time I deal with free trade I'll pay special attention in order to try and answer some of your questions.

Jerh9e1k5

[Caligula 37 AD]

oh-please, just call me Cal..

[Hauptman]

ya got a few hits off mark cal, Mercantilsm does NOT give you trade routes, its free market that does. Merc. actually HURTS trade routes by making you trade with your own cities only.

The max # of trade routes i have seen is 6. before you obsolete the Great Lighthouse, and then again after you build airports. These add trade, wich is affected my the "slider" and all your buildings. so having 6 trade routs producing 8+ trade each is like having 6 gold mines in your city square. trade routes are KEY. Live them, learn them, love them.


The way they get set up I believe is that your top (largest perhaps, maybe oldest, not sure) city checks those cities that have Open Borders with it. The top city they have then shares a route with yours. you BOTH get the trade route bonus from each other. then it continues down the list, some cities just arent worth as much so some dont give as much. If you donot have open borders with anyone, or you run mercantilism then you can only have trade routes with yourself... as the few times ive used or seen this, my trade routes went from 12+ to 5... OUCH. I'd rather irrigate 1 more square and trade 1 more luxury to get those extra specialists.

[Blake]

The quality of trade routes a city attracts is calculated approximately like this:
Population.
Double for presence of harbor.

That's simple enough. It seems to then rank cities by age.

For example:
You have a size 20 landlocked capital. Your best coastal city is size 10. Both have the same rank, but the capital gets the best trade routes.

The VALUE of a trade route is determined by the population of the city is it coming from. This is further modified by your own cities population and the harbor.

Example:
Your city is size 20, it is trading with a size 15 city. The trade route might be worth 9. Building a harbor might increase that to 10 (a 11% increase).

Your city is size 7, it is trading with a size 15 city. The trade route might be worth 6. Building a harbor might increase that to 10 (a 67% increase).

The Rule: Harbors have the MOST effect in a SMALL city trading with LARGER cities. They have the LEAST effect in a LARGE city trading with SMALL cities.

In effect a harbor bumps up the effective size of a city, allowing it to make the most of trade routes with larger cities. If however your city is already huge in comparison with it's trading partners, it doesn't need the harbor to make the most of trade routes.

One of the curiosities of the one-way trade routes system is that most cities are trading with cities smaller than them, this makes harbors only really wortwhile in your 2-3 largest cities. However they can be extremely worthwhile in those 2-3 cities, I've seen increases in trade income of over 60% in the first city I've built a harbor in (the bonus is very much not a flat +50%).

[alimac]

Hi all.

This is my 1st post on here.

This trade routes system seems noticably more complex than before. I must admit certain areas really have me puzzled. A couple of my cities have established trade routes with foreign cities without any negotiations by me or notification. I simply opened my city page and there was a trade route! Do I not have to negotiate these before they are opened?
I know it's been said before but to clarify: is it correct that a city needs to be connected in some way (road, river or sea) to another for them to trade?

Also another quickie. I cannot find anywhere to demand gold on the diplomacy screen. I'm sure someone can help me here!

[Arrian]

No, the trade routes get set up automatically.

You can demand gold, but you have to have a certain tech (currency?).

-Arrian

[Caligula 37 AD]

First, thanks Hauptman. Yes it is Free Trade giving +1 trade route per city. And that takes the mystery off the civic as well. :standing corrected:
I didn’t have my game present when writing the post, so I got a bit confused.
Still I’m not sure what the Global civic, Free Market does, and so the questions above applies now for this

It also seems the maximum #trade routes is 6.

Viewing through my screenshots there is something else smelling of halibut, Blake:

In the AU game (which I must get around to finish soon..), just before I hit modern era I went through all cities making screenshots (1690AD) .

Here is a list of population, trade routes, age, and presence of harbors in them all:

Washington(20) Capital, founded 4000BC, inland, trading with:
New York(domestic) (+2)
Turfan(foreign) (+2)
Illinois(foreign) (+2)

New York(13), founded 3360BC, coastal, harbor, trading with:
Memphis(foreign) (+6)
Thebes(foreign) (+6)
Heliopolis(foreign) (+6)
Barclona(foreign) (+5)
Cordoba(foreign) (+5)

Boston(11), founded 3000BC, coastal, harbor, trading with:
Sevilla(foreign) (+3)
Hastings(foreign) (+3)
Damascus(foreign) (+3)
Baghdad(foreign) (+3)
Najran(foreign) (+3)

Philadelphia(12), founded 1960BC, coastal, harbor, trading with:
Madrid(foreign) (+5)
Canterbury(foreign) (+5)
Mecca(foreign) (+5)
Medina(foreign) (+5)
Beshbalik(foreign) (+4)

Atlanta(12), founded 775BC, coastal, harbor, trading with:
Elphantine(foreign) (+4)
London(foreign) (+4)
York(foreign) (+4)
Nottingham(foreign) (+4)
Alexandria(foreign) (+3)

Visigoth(13), founded 1440BC (captured 50AD), inland, trading with:
Toledo(foreign) (+2)
Santiago(foreign) (+2)
Coventry(foreign) (+2)

Yayoi(16), founded 1560BC, (captured 680AD) coastal, harbor, trading with:
Karakorum(foreign) (+6)
Berlin(foreign) (+6)
Hamburg(foreign) (+6)
Munich(foreign) (+6)
Cologne(foreign) (+6)

Chicago(9), founded 820AD, coastal, harbor, trading with:
New York(domestic) (+2)
Philadelphia(domestic) (+2)
Ninghsia(foreign) (+2)
Old Sarai(foreign) (+2)
Samarqand(foreign) (+2)

Seattle(9), founded 1180AD, coastal, harbor, trading with:
New York(domestic) (+2)
Yayoi(domestic) (+2)
Frankfurt(foreign) (+2)
Essen(foreign) (+2)
Dortmund(foreign) (+2)

New Sarai(4), founded 920AD, (flipped to me 1300AD), coastal, NO harbor, trading with:
Washington(domestic) (+1)
New York(domestic) (+1)
Boston(domestic) (+1)
Philadelphia(domestic) (+1)
Atlanta(domestic) (+1)

San Fransisco(10), founded 1340BC, inland, trading with:
Kufah(foreign) (+2)
Washington(domestic) (+1)
New York(domestic) (+1)

If your assumption regarding the harbors is right (and it looks like it is), the cities will get a “Trade partner score”, equal to city size and doubled by harbor, and given the best routes according to this.

The order (and score) in my case: Yayoi(32), New York(26), Philadelphia(24), Atlanta(24), Boston(22), Washington(20), Chicago(18), Seattle(18), Visigoth(13), San Fransisco(10), New Sarai(4).

Finally my point: (And this is what smells fishy)
Washington is by far the most improved city, but is only the sixth favorable trade partner. In this case my harbors in Yayoi, New York, Philadelphia, Atlanta and Boston are actually hurting trade, giving the best trade routes to less improved cities. And they do not seem to give any other effect in this case. I can’t see any +50% for the value of the routes. Seattle and Chicago should have had some +3s if it did. (This again might support Blake’s thumb rule of building it only in a few cities.)
Blake: are you sure your boost of 60% when building the harbor isn’t due to “stealing” better trade routes from other cities? I.e. was it the same route boosting ~60%, or did it attract a new and better partner?

Mind you, this picture was taken before v1.52, maybe it is altered. If it is not, the rule of thumb from me is:
Don’t build Harbors! Your larger cities are already at the top of the list, your smaller cities shouldn’t have them as they only steals from your larger ones.
-Unless it is a city with greater modifiers for science/gold than your larger ones
-Unless you want to make sure your coastal capitol stays at the top of the list.

Further investigations should be made.

- Cal