How are trade routes determined?

[jpinard]

I see I've got a lot of cities trading with potential enemies. Is there a way I can change this? Or a way to "cut them off from trade"?

 

[sumit1207]

Cancel open borders with them. I'm not sure if there is any other way.

 

[Lurking Liu]

I don't know how the specifics work, mind you, but the AI calculates the most lucrative trade routes and then sets them up automatically. If that's an internal trade, then it's an internal trade. But it's always optimal, as far as I can tell.

 

[Sephlock]

Is it just me or is the whole trade route thing rather... vague?

I mean, give me a dotted line, an arrow, SOMETHING.

 

[Yzman]

Yeah I never quite understood trade routes. I didn't even know they need open borders.

 

[Lurking Liu]

You need Open Borders and a way to contact them, which is why Sailing is a really clutch tech on the right maps. Getting Sailing will put you in contact with all civs along your coast, while otherwise you're going to have to build a road all the way over to them. (Or build a road to a river that goes into their territory so long as they have a road to it, also)

 

[jpinard]

I've had this since the original Civ was released and never knew it... though never bothered to ask either.

I guess this is why my pathetic Viking neighbor wants open borders so bad - hehe. I'm rich!

 

[hoopsnerd]

yeah, trade routes can be huge on a "archipelago" start. Build the great lighthouse and your tiny 1 population coastal cities can bring in 16 commerce per turn... (well, I was Hannibal...) that covers maintenance .

Also note that a UN resolution allows you to trade with everyone, even it you dont have Open Borders and I presume even if you are at war... but i never personally checked the war thing.

 

[Thalatta]

The Great Lighthouse is an amazingly strong wonder. It's one of the main ways that I use to fund expanding heavily early on - cities with four trade routes (assuming currency) that can work coastal tiles when the commerce is needed can keep you well afloat. (Pun intended...)

 

[hoopsnerd]

The Great Lighthouse is an amazingly strong wonder. It's one of the main ways that I use to fund expanding heavily early on - cities with four trade routes (assuming currency) that can work coastal tiles when the commerce is needed can keep you well afloat. (Pun intended...)

PLay hannibal and rush to optics... 5 trade routes.

 

[Thalatta]

Well, and Compass is on the way...man, I love Harbors.

 

[hoopsnerd]

Well, and Compass is on the way...man, I love Harbors.

Cothons are the best UB the great lighthouse has ever seen .

 

[Thalatta]

Can you tell I don't play Hannibal much? I had a lot of fun playing Joao; having Feitorias and The Colossus is like being financial! The only problem with lots of trade routes is that sometimes you end up with more routes than there are available cities to trade with and you end up with domestic routes.

 

[hoopsnerd]

Can you tell I don't play Hannibal much? I had a lot of fun playing Joao; having Feitorias and The Colossus is like being financial! The only problem with lots of trade routes is that sometimes you end up with more routes than there are available cities to trade with and you end up with domestic routes.

Hehe true... however if you rushed to Optics to get the Cothon, then you can explore with your caravels all over the map while you rush to liberalism in order to pop Astronomy. Watch your economy the turn you hit astronomy and the extracontinental trade routes kick in.... especially if you build artemis in your capital .

 

[Unthinking Pain]

Harbors/Cothon come from Compass, not Optics.

Great Lighthouse makes Cothons less impressive, not more so. With 4 trade routes already, Cothons are 25% improvements (at best... the 5th trade is probably not nearly as good as the first 1-3.) With 2 trade routes, Cothons are 50%. % growth is the name of the game IMO.

It's the same way that Financial's least important commerce improvement is Towns, because Towns already give a significant amount of on their own. Financial really shines when you are working a lot of 2-4 squares. I love getting in windmills/watermills with Electricity + Financial.


EDIT - http://forums.civfanatics.com/showthread.php?t=159047 for how trade routes work.

 

[hoopsnerd]

Harbors/Cothon come from Compass, not Optics.

Great Lighthouse makes Cothons less impressive, not more so. With 4 trade routes already, Cothons are 25% improvements (at best... the 5th trade is probably not nearly as good as the first 1-3.) With 2 trade routes, Cothons are 50%. % growth is the name of the game IMO.

It's the same way that Financial's least important commerce improvement is Towns, because Towns already give a significant amount of on their own. Financial really shines when you are working a lot of 2-4 squares. I love getting in windmills/watermills with Electricity + Financial.

You've obviously never done this, and yes I realized my mistake its Optics not Compass, whatever. We aren't talking about "Financial" or towns. Hannibal happens to be financial, but it has nothing to do with trade routes. If you've ever looked at your trade routes, you'd notice that the most valuable trade route is not much more valuable than least most, as almost 100% of the time the "base profit" is either 1 or 2 commerce and is then multiplied by bonuses. We're talking about an island cities having 5 trade routes producing ~4 commerce each for a size 1 city in the early game. Why is that significant? Because a coastal or island city doesn't have to grow to semi-maturation to cover it's maintenance costs, even if its further away from the capital. Why is that significant? It allows you to expand much more rapidly and vastly than you otherwise could if you settle mainly coastal cities. The cities will be somewhat productive in terms of commerce the instant they are founded. It doesn't even matter if the trade routes are domestic or not, although it's slightly better if they are not. Intercontinental trade still kicks in even if it's an island city.

Realize that civ is all about stacking subtle bonuses on top of each other for maximum effect... Thats why we specialize cities.

 

[Thalatta]

Seeing as trade routes get optimized, more seems almost always better to me. I see the argument against diminishing returns, but I think in this case it's actually not about % growth. Here's a numerical example:

2 trade routes @ 2 each, third one 2 also - increase from 4 to 9
4 trade routes, 3 @ 2 each, 1 @ 1, fifth one 1 also - increase from 7 to 12

In this case the % increase is higher without the Cothon, but the commerce increase is the same - and the raw commerce number is what I would consider to matter more.

 

[hoopsnerd]

Seeing as trade routes get optimized, more seems almost always better to me. I see the argument against diminishing returns, but I think in this case it's actually not about % growth. Here's a numerical example:

2 trade routes @ 2 each, third one 2 also - increase from 4 to 9
4 trade routes, 3 @ 2 each, 1 @ 1, fifth one 1 also - increase from 7 to 12

In this case the % increase is higher without the Cothon, but the commerce increase is the same - and the raw commerce number is what I would consider to matter more.

The 50% growth is trivial compared to an extra trade route because it's only .5 times the Base Profit of the trade route, which is almost always 1 Commerce in the early game. So the 50% trade route bonus (assuming 4 trade routes) would give you only +2 commerce per turn. An extra trade route should always produce more, as it gives you at the very least +1 commerce per turn for base profit and is almost always multiplied by some modifier (ie: 100% for extra-continental). The real power, as is with any bonus in civ, is stacking these seemingly "trivial" bonuses together until you have something significant. The 'extra' trade route from the Cothon stacks with the 50% trade route boost it also gives, giving you an extra 1.5 commerce per turn minimum when compared to a harbor. That effectively almost doubles the effectiveness of the Harbor in the early game. It is true that your last trade route will be less optimal than your best, but only slightly, and the returns from the 4th and 5th trade routes are only as diminished as the portion of the map you've explored. Granted, this strategy isn't quite as great if you have a lot of places to build cottages, but if you start on an island or have an island chain nearby, it's huge.