Discussion in 'Civ4 Strategy Articles' started by KrikkitTwo, Feb 13, 2006.

1. ### CrightonEmperor

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I have a question:

Is there a way to code it so that there are a number of Trade Routes in a city equal to say half of the population?

For example: A city with size 20 could have up to 10 trade routes?

(i'm assuming there are other alterations allowed to be past that hurdle of six routes mentioned above)

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3. ### Qitai.

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Just want to note that Harbor is probably calculated as a subresult and not after taking the min of 2 for foriegn trade. Noted this because I have some cities with +2 from foriegn trade trades before harbor and remains the same after that for a long time even after. So, it looks to me that it is calculated before taking the min of 2. This affects my decision to research Compass and building harbor.

4. ### Roland JohansenDeity

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Do foreign trade routes have a minimum of 2 commerce? I didn't know that. Are you sure?

5. ### cabertBig mouth

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Well, the minimum for a trade route is 1, foreign trade routes have double output, making a minimum of 2. Makes sense to me.

However, i often have closed borders with half the world and that makes foreign trade routes quite less in numbers, so i get them in the best cities only. That makes it almost impossible that they could get rounded under 2.

6. ### Roland JohansenDeity

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Yes, I know that trade routes have a minimun trade value of 1 (from experience, not from xml entries). This value multiplied by 2.5 and rounded down leads to a minimum of 2 for foreign trade routes. However, I don't know if the minimum value of 1 is applied before or after the value of the trade route is multiplied with 2.5. As I also have not seen a foreign trade route valued lower than 2, I agree that it is most probable that the minimum value of 1 is applied before the trade route value is multiplied with 2.5.

7. ### cabertBig mouth

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world builder is your friend :

a world with you and an AI, each one has just one size 1 city, a road between the 2 and open borders (put those 2 city at distance 3). Should be the worst conditions for trade routes. If you get a value of 2, then you know there is no way to get a lesser valued foreign trade route.

Would do it myself, but when i've got my hands on a computer with cIV, i can't stop playing

8. ### Qitai.

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Never seen a situation where the foriegn trade route is 1, so until there is a counter-example, I assume this statement to be true. Also, the fact that the harbor add nothing to my smaller cities (with four trade routes) seems to indicate the same thing. So, I am fairly confident that this minimum exist.

9. ### Roland JohansenDeity

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Okay, I believe!

10. ### Lord ChambersEmperor

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So shouldn't a foriegn trade route have a minimum value of 3 in a city with a harbor? I don't understand where 2.5 comes from. Harbors increase trade by 50% right?

11. ### Qitai.

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Well, that is exactly what I am highlighting here. The harbor effect seems to be calculated BEFORE taking the minimum. So, if the yield was originally very low, the harbor gets you nothing. I thought it would give me 4 commence since I had 4 (+2) foriegn trade routes, but it gives me nothing. So, the production was wasted as I do not need the health bonus in that particular game.

12. ### KrikkitTwoImmortal

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Well for a Foreign route to get a base value of 1 it would need to be a Foreign city that was less than ~15 population. (with a domestic city that was 1 population)

Now with a Capital of population 5, and a Foreign city of population 5, you could get a value of 1 theoretically. So since that doesn't seem to happen (which it probably would in a normal game), I can guess that the minimum is applied before the Foreign effect. The Harbor is therefore probably applied before the minimum, as a minimum 1* Harbor*Foreign, rounded down, should give 3 which it doesn't.

However, if the Rounding is done at the last step, then the Harbor can still have a benefit (and it appears to... raising some domestic "1's" to "2's"). However that benefit requires the trade route to have a domestic value of at least ~1.34 or a Foreign one of 2, which means.
A Foreign route between two Pop 8 cities.. at a distance of about 8 tiles
or
A Domestic route between two Pop 10 Cities , at a distance of about 10 tiles.(distance being a distinct problem for domestic routes)

Those are probably very achievable with any city (even ice fishing villages can get population) So even if the harbor isn't profitable now, it will be

13. ### Qitai.

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Yes, no doubt about that the harbor will eventually be very useful. It is the timing which I am looking at. It was at a time when I had mostly size 6-8 cities when I am consdering if I should research compass and build harbor. I went for it only to find out it did not help at all wasting both my reasearch points and production which could have been diverted to other items.

14. ### Lord ChambersEmperor

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I probably build harbors too early.

I usually build them when I've got the Great Lighthouse, so I always assumed a good level of synergy.

15. ### KrikkitTwoImmortal

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That probably is just about right, assuming you have decent trading partners. It'll only be profitable for a few cities but they should become more profitable (and for the purposes of size a Capital counts as if it had 5 extra population... so it would at least probably be worthwhile in your capital immediately.) soon.

So at that point probably go for it but don't rush it (something more urgent should come first.)

16. ### PaeanblackPrince

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Given how other +x% items seem to work, it's quite possible that a foreign trade route is minimum 1g+100%, and a foreign trade route with harbor is 1g+150%. This would give the 2.5g you are seeing.

17. ### cabertBig mouth

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it seems the rounding is done after the +50% from harbor
So you don't get anything more in small cities from the harbor.
Don't build it if you don't have health problems and the city isn't at least size 6.

18. ### snöflingaChieftain

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I'm still very confused . I don't even understand the basics of this 'trade route' system and can't find it anywhere . When I run a search, I usually get directed to the 'ideas' section of how other people would like it set it up, but never an explanation of how it works in applicable terms, other than very technical formulas . Can anyone help explain this at a basic level? Please?

Take me through, ok, I have a civilization, let's say I have five cities...now what happens? How do my trade routes get set up? Why can't I choose them? What does it mean I can only have so many foreign trade routes and who gets to choose those, and do they only happen if there's 'space' or a trade route available? and so when the mighty Isabella offers me clams for fish, does that mean only one or none of my cities may benefit?? I'm sorry for not understanding this at all, but I can't find anything that describes it and I miss my little trade advisor . (I also miss that Elvis advisor from the early days, he was funny.) Is there a link or a detailed guide on trade routes already out there somewhere that someone could direct me to?

19. ### trianglmanChieftain

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I will try to sum up what I understand as best I can, anyone out there correct me if I am wrong on any of these points.

First, there is a difference between foreign trade routes and resource trading. Trading with Isabella to get clams gets those clams for any city connected, via roads and rivers to your capital.

Trade routes are created for each city, up to the limit that city has (different civics, techs, and buildings can increase the number). The trade routes are calculated, as I understand, from most valuable to least valuable depending on what a given city is connected to, again via roads and rivers. If you have those five cities, all of them interconnected, but not connected to any foreign city, each city will select trade routes starting with the most valuable, probably your capital.

If each city has three available trade routes, the capital will connect to the three most valuable cities, the second most valuable will then have two trade routes to connect to the next most valuable cities, etc. The fifth city though, won't be able to create a trade route with your other cities however, because all of the other cities have used up their available trade routes, and so will have no active trade routes.

The complex calculations in the other posts calculate how much commerce you will receive for each trade route.

I hope this helps some.

20. ### snöflingaChieftain

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This does help! . Thank you . I do understand now! (at least the basics of the basics) yay!

I only have two small questions left:
1) do the trade routes update automatically each turn (or after a set amt of turns)?? I would assume so since a civilization keeps building...and therefore the best routes 300 turns in the game are obviously different than those after 35 turns in the game, but maybe not...
2) hmm, so the foreign routes are automatic too? If I had open borders and coastal cities, and once I had astronomy, my capital could just automatically pick a trade route to a foreign city that also had coastal cities?

Thank you again and sorry if these are basic questions, but I do thank you for the time you took to explain this to me .