Trade Routes 101

[inca911]

First of all, I'm talking about vanilla cIV. There are things I know about trade routes, but I must be missing something as the routes don't seem to behave as I expect. I know all the AIs but the routes don't seem to add up correctly. Most of my games ays are OCC with many small islands (to enable coastal trading), and I'm back after a long hiatus, so many of my questions will likely be easy to address.

We know that Sailing is needed to enable coastal trade routes with other civs. I typically use a work boat for early exploring (and frequently circumnavigate the globe with that one workboat). Do I need to actually "see" a foreign city to have it be a potential trade route partner, or just meet the foreign leader? Do I need to sail my boat next to the city or even into it to establish a route, or drop off a land unit to reach non-coastal cities?

Is the first trade route "free" once contact is established, or is there a tech that is needed for the first route (i.e., With Currency, should I have one or two trade routes)?

Does a civ have to have open borders to be a trading partner, or do open borders only increase the trading bonus?

Currency gives one trade route.

Compass = Harbor, and Harbor increases trade route bonus by +50%. Is this all routes, or only coastal/ocean routes?

Astronomy enables trade routes on the ocean (not just coastal).

Flight = Airport, and Airpost gives one more trade route.

Economics = Free Market, and Free Market gives one more trade route (if you implement that civic)

Corporation gives one more trade route.

Great Lighthouse = +2 trade routes (obsolete with Corporation).

Banking = Mercantilism = no foreign trade routes if the civis is implemented (explains why routes can disappear around Banking time)

I also think the is a UN vote than can be used to increase trade routes by 1.

Anything else I'm missing? Trade = commerce = win in my world, so thanks for any insights and answers!

[snoopy369]

Open borders are required for trade routes of the gold-giving variety (as opposed to trading resources which is fine for any at-peace civ).

Trade routes 102: You basically have a pool of "all available trade routes", which is (1 of every foreign city you have OB with) plus (infinite of your own cities). Each city is given a "weight" which roughly relates to how profitable a trade route is with that city (but not precisely, Harbors modify this so a harbor city more likely gets trade routes than it ought). Then the trade routes are assigned in order of most highly weighted (roughly equal to most profitable).

Things that make a trade route more profitable: Direct modifiers (harbor), city size, distance, and I think a few other things (maybe palace?). Bank/etc. does not as far as I know, so there is a significant risk if you use a harbor to draw trade from one city which has a wall street or oxford university, that you may actually lose mony with the harbor.

You generally have the rest of that right, I believe, though I haven't played Vanilla in years.

Open Borders is definitely the big bonus, it gives you a TON of free commerce. Of course it gives the same to the other civ, so be careful of having OB with the tech leader. If the number of available foreign trade routes is greater than the number of available trade routes then it won't matter, but that rarely happens; most of the time, cancelling open borders with a civ will directly take money away from that civ (and from you as well of course). There is a great advantage to keeping the tech leader from having OB as much as possible

[darrelljs]

Re: Trade Routes 101

Originally posted by inca911
Do I need to actually "see" a foreign city to have it be a potential trade route partner, or just meet the foreign leader?

Sorry, can't help with this one although I don't believe map info plays a role its just a guess.

Do I need to sail my boat next to the city or even into it to establish a route, or drop off a land unit to reach non-coastal cities?

Nope.

Is the first trade route "free" once contact is established, or is there a tech that is needed for the first route (i.e., With Currency, should I have one or two trade routes)?

You need to be connected to the foreign civ's trade network to be eligible for trade routes to their cities. Techs like Currency will give you extra trade routes, but play no role in trade route selection (although if you have lots of trades routes odds are some of them will be of the crappy domestic variety).

Does a civ have to have open borders to be a trading partner, or do open borders only increase the trading bonus?

They must have open borders and not be in Mercantilism.

Compass = Harbor, and Harbor increases trade route bonus by +50%. Is this all routes, or only coastal/ocean routes?

Mmm...so far as I know Harbors don't actually increase the commerce, they make the city 50% more attractive and thus it will have better routes. I believe a Customs House actually increases the route value, but that's just a guess and it is only in BTS.

Optics enable trade routes on the ocean (not just coastal).

Nope, Astronomy does this.

Flight = Airport, and Airpost gives one more trade route.

Yes. You can get extra trade routes from Currency, Corporation, Castles (until they obsolete), Cothons, The Great Lighthouse, Airports, a U.N. resolution, and the Free Market Civic. Since you are talking about vanilla Cothons and Castles don't apply to you.

Anything else I'm missing? Trade = commerce = win in my world, so thanks for any insights and answers!

Well, there is a wonder in Warlords/BTS that gives 100% boost to trade route yield, so for OCC trade route games you might like that. Maybe you should go purchase BTS .

Darrell

[inca911]

Example:
So if I have open borders with Ghandi, am I limited by his number of trade routes? As a specific example, if he only has 2 routes possible, does that mean I can only have two routes, even if I have the potential for many more? That might explain why the route numbers aren't adding up.

[snoopy369]

No. You have a pool which is 1 of each of his cities plus (infinite) of each of your cities (plus any other OB you have, 1 each). Thiis is irrespective of his trade routes and is in fact irrespective of his ability to have trade routes with you - in other words, if you can see a path to his cities but he can't see yours, you get trade routes, he gets nothing.

So if he has seven cities, you have seven trade routes, one with each of his cities, that are assigned to your cities in the order of largest (pure commerce) returns. So Delhi is one trade route, Bombay is one trade route, Madras is one trade route, no matter how many (0 - infinite) trade routes each of them earns.

[inca911]

Originally posted by snoopy369
...if you can see a path to his cities but he can't see yours, you get trade routes...

Thanks for the clarification. Per the above text, it sounds like I need to simply "see" the location of the city to establish a route and that physically touching the city square (or cultural border) of his city with one of my units is not necessary. If I haven't "seen" a city of his, then it isn't an option as a trade route (for the calculation of most lucrative trade routes) so moving inland to visually uncover large cities is likely worth the effort. If "seeing" a city is necessary, then sharing maps could be very valuable in getting the best possible trade routes.

[greenday_234]

Does Merchantalism also cut off the ability to trade goods for example:

Under merchantalism I will not be able to trade 10gpt or any other resource for furs or any other resource?

[snoopy369]

I don't believe you need to see the city; just see a route to the city. This is subtly different, because you don't have to know there's a route to the city

Most of the time, when talking about a civ with contiguous cultural borders and trade amongst all of its cities, you will only need a traceable route from your city (or hopefully network of cities) to their cultural borders. Across land this is easy - just build a road to them, or connect to a river that connects to them. Across sea, you need either a continuous set of coast, or Astronomy and a continuous route across the ocean.

I've often had trade with cities i've never seen before It can be an effective way to do a bit of low key espionage - you can tell the largest cities in a civ by seeing who your largest city that trades with that civ is trading with

Also, it is a good reason NOT to share maps. If you were the 'explorer', you would want to get OB as soon as possible; then you'd start profiting off of the trade routes right away, while he wouldn't profit until he finds your borders (visually).

Greenday, no, mercantilism only negates trade routes in the commerce sense. You can still manually trade gold or goods.

[rjmatsleepers]

Re: Re: Trade Routes 101

Originally posted by darrelljs

...
Mmm...so far as I know Harbors don't actually increase the commerce, they make the city 50% more attractive and thus it will have better routes. I believe a Customs House actually increases the route value, but that's just a guess and it is only in BTS.
...
Darrell

My understanding is that Harbours (or Cothons) have two effects. Firstly they modify the position of the city in the allocation list (the "pool" mentioned by Snoopy369). I've heard it said that the new position is roughly equivalent to a city of twice the size it actually is. Secondly, they increase the value of the route by 50%. However this is rounded down, so a value 1 route remains value 1.

As Snoopy369 pointed out, the change in the allocation of routes can take the high value routes away from an inland city with many modifiers which could reduce or eliminate the benefit from the harbour.

RJM

[Edit] In the final bit above, I mean the trade benefit. The health benefit is not changed. [/Edit]