How To Maximize Trade Between Two Cities?

[rjmatsleepers]

Trade route anomoly?

This example does not involve foreign trade, but it does show a lower value route replacing a higher one. Unfortunately it involves hides which may be significant.

There is a hide caravan from Avalon about to be delivered to Gloucester. Gloucester has 3 existing routes - 2 with Camelot and 1 with New London. Camelot has a base trade of 9 arrows while New London has a base trade of 8 arrows. Avalon has a base trade of 8 arrows. However the delivery of the caravan displaces one of the Camelot routes.

Am I miscounting the base trade? Have I misunderstood the way in which routes are supposed to be replaced? On the face of it, what happens here does not conform to the "rules".

RJM at Sleeper's

[Zenon]

RJM, I have checked your example and agree that the replacement of the trade route is not as predicted. On the other hand, this seems to be a special case. Gloucester shows 2 trade routes with Camelot while Camelot only shows 1 trade route with Gloucester (no other trade routes). I suppose that Camelot is a hides repeater. Gloucester is a hides demander. When delivering the same commodity again to the same destination city the destination city gets another trade route whereas the source city does not. That´s obviously what happened on the Gloucester/Camelot trade route. Avalon also has delivered hides to Gloucester allready and is now delivering hides again. What happens here is the replacement of one incomplete trade route by another. May be that´s the reason. Anyway, a very interesting case that leaves some questions open.

Zenon

[Elephant]

Trade Route replacements and domestic route values are bedeviling me too. Sometimes a new delivery replaces an existing one, sometimes it replaces one from a different city. I've been doing control tests with a "cheat" map, but the reasoning behind the differences still escapes me. And I've seen several cases where the value of a route between two of my cities has been off by 1. I will look into the issues of one-way routes and whether Hides makes for special cases.

Thanks for giving your example with a 2.42 save, too.

[rjmatsleepers]

Originally posted by Elephant
I will look into the issues of one-way routes and whether Hides makes for special cases.

I believe that I have had the same thing happen with deliveries of goods other than hides, but unfortunately I can't find a save to show it at the moment. And in any case, it may be that one of the routes involved was originaly set up with hides.

RJM at Sleeper's

[rjmatsleepers]

Originally posted by Zenon
When delivering the same commodity again to the same destination city the destination city gets another trade route whereas the source city does not.

Zenon

BTW, is this true of any commodity or just hides?

RJM at Sleeper's

[Zenon]

Thinking of this problem again it might also be that replacement works sometimes differently if the values are very close. In RJM´s example it was only one beaker. If you take one more beaker from the trade base from New London the trade route is replaced as expected.

RJM, not getting a trade route in the source city when delivering the same commodity to the same destination applies for any commodities, not only for hides. But that´s a rare case unless rehoming is used.

Zenon

[rah]

Yes, prior to outlawing rehoming in our MP games we saw a lot of strange things.

[Zenon]

Indeed, the creativity in inventing exploits that have to be banned again in MP games is admirable. BTW, does Rah - Rules stand for Regularly abandoned hoaxes?

Zenon

[rah]

Hmm, I thought it was Routinely Approved Hijinks.
But your's will do.

[sirsnuggles]

Doh! Looks like Elephant posted while I was away. His calculations are correct except for a couple of exceptions (to be redundant).

1) Corruption lowers the value of base trade a city produces
2) Corruption lowers the value of the resulting trade routes (Hence if you change the gov to democracy you will see what the real trade route value is). Even though the true value of a trade route should be 10, high corruption would lower that amount considerably.

For example:
Tianjin (Chinese) has a trade route with Lyons (French). Both governments operate under Monarchy.
The base trade for Tianjin is 41, Lyons 48.
The trade route should be (41+48+4)/8 = 11.
Now corruption lowers the base route to 17 (Tianjin is a far away from Beijing; distance = 24) and 39.
(17+39+4)/8 = 7.
Now, because of corruption those additional 7 arrows will be reduced by 4 to 3 (7-4=3) arrows.

If Tianjin benefited from a road bonus, then the 7 would be modified to 10 (7*1.5), and reduced by corruption to 4 (10-6=4).

Hence, Tianjin's total taxable trade (under monarchy) will be 17 + 3 = 20.
A change to democracy (for both Chinese and French governments) would result in a much greater taxable trade: 41 + 11 = 52. That's a hefty difference.

Note: the arrows after corruption are what are modified by the road, RR, etc bonuses.
3) Also, the bonuses derived from roads and railroads are not cumulative with the airport bonus. When an airport bonus exists in a city, if that city also derives either the road or railroad bonus then the airport bonus is eliminated.

Here's a table:
Road = +50%
Railroad = +50%
Airport = +50%
Road & Railroad = +100%
Road & Airport = +50% (not 100%)
Road & Railroad & Airport = 100% (not 150%)

4) As I think Elephant was saying, the continental location of cities with airports does not affect trade routes, i.e. you get the bonus regardless of what continent (same or different) the cities rest upon.


I built a spreadsheet several months showing the exact formulas used, but I haven't posted it yet. Since I just lost my job yesterday, I might have the time to post a presentable version. My spreadsheet covers nearly all of the calculations in the game (concerning city production).

If anyone has questions...well I'm sure you'll post them.

[sirsnuggles]

PS. Whenever a new trade route is established, the computer always chooses the highest three trade routes. Hence it is important to calculate them correctly by accounting for corruption when predicting which three the computer will choose. If you fail to account for corruption then you will be surprised when a new trade route that you thought would be high isn't chosen-corruption decimated that high trade route.

Yes, when a source city establishes a second route with the same city of a commodity already being supplied, that source city will not gain an additional trade route. In other words, all three trade routes must be unique in regards to city and commodity. A source city can supply two hides routes, but they must be to different cities.

[rjmatsleepers]

Originally posted by sirsnuggles
PS. Whenever a new trade route is established, the computer always chooses the highest three trade routes.

This is not the case - see the example I posted above where there is no corruption in the source cities and yet the new route does not displace the lower value route from New London. But as Zenon points out if New London is reduced by 1 arrow, it does get replaced. Zenon also points out that the anomolies happen when the values are close. Could the algorithm be more complex than we realise and involve some rounding?

RJM at Sleeper's

[Scouse Gits]

Since I just lost my job yesterday,

That sounds like bad news -- I'm sorry.

Stu

[Elephant]

Originally posted by sirsnuggles
3) Also, the bonuses derived from roads and railroads are not cumulative with the airport bonus. When an airport bonus exists in a city, if that city also derives either the road or railroad bonus then the airport bonus is eliminated.
...
4) As I think Elephant was saying, the continental location of cities with airports does not affect trade routes, i.e. you get the bonus regardless of what continent (same or different) the cities rest upon.

My testing was not rigorous enough. I noticed that the Airport bonus was not taking effect between two cities on the same continent; I had just finished testing RD/RR bonuses between those cities, and did not remove them to test independently. Airport bonus did effect cities on different continents, but there was no RD/RR bonus then. Mea Culpa. I shall restest Airports more carefully. Thanks for catching that.

Practically speaking, I always shoot for RailRoad, then SuperHighways, and leave Flight off as long as possible to extend Colossus, so Airports are late-game, low-priorities (but they do help move freights faster). All this really means is that the best we can do with the Transport Multiplier is +100% for RR on the same continent, and +50% for Airports on different continents. Early game, the bonus payments for deliveries off-continent are higher, but once the RR line is ready that will be the cash cow for the SSC. Building that line, and keeping it from getting blocked by maintaining an alliance, and using that alliance to help the AI city get as much trade as possible, should be the primary foci of those seeking maximum Trade Routes.

[sirsnuggles]

I concur with your assessments.