22-04-2004 02:09									#1
	Trade Route Formula Support Apolyton, buy Call to Power 2

This new thread pulls together data on Civ2 Trade Route formulas from several previous posters and threads, most importantly the How to Maximize Trade Between Two Cities:
http://apolyton.net/forums/showthre...&threadid=90878

The Basic Formula comes from the Civ2 Manual; the Multipliers and their order are based on Samson's Calculating Caravan/Freight Delivery Payments:
http://apolyton.net/forums/showthre...&threadid=64729
NOTE: This thread attempts to formalize the "ongoing" Trade Routes, not the one-time Caravan/Freight Delivery Bonus.

All multiplication and division are Civ2 integer math: remainders are dropped.

BASIC FORMULA: TR=(T1+T2+4)/8
T1 and T2 are "Total Base Trade Arrows" of Source and Dest cities
Base Trade Modifiers:
- (-1) in Despotism for each tile that has >2 trade arrows
- (+1) for each land tile with River
- (+1) for each road on Grass/Plains/Desert tiles
- (+1) for each road on tiles with >0 arrows ("special" tiles or rivered)
- (+1) in Rep, Dem, or Celeb-King/-Commy/-Fundy for each tile >0 arrows
- (+1) for Colossus for each tile >0 arrows
- (x1.5) with SuperHighways for each land tile >0 arrows with road/railroad
- (x???) Base Trade Corruption Loss

TR MULTIPLIERS (apply in order listed, discarding remainders):
...(NO Map Size multiplier)
1). (x???) Secondary Corruption Loss (first or last?)
...(NO Different Continent multiplier)
2). (x0.5) Same Civ multiplier
...(NO FreightVsCaravan multiplier)
...(NO Demand multiplier, just Dem/Sup blocking effects)
3). Transportation multiplier(add together before multiplying?):
+50% for KeyRoad Source->Dest(alt: StationCity; limit: 22), OR
+100% for KeyRR Source->Dest;
+50% for SuperHighways in Source city (increases BaseTrade too);
(NO+100% for SH in both cities, just Dest Base Trade increase)
+50% for Airports in both cities, same or diff continent
(NOTE: Airports Factor superceded by RD/RR Factor!)
...(NO AgeModifier)

Rules of Thumb:
BEST: Same Continent KeyRR with SH to AI city (+150%)
NEXT: Diff Continent SH, AP to AI city with AP (+100%)
SAME: Same Continent KeyRD with SH to AI city (+100%)
OWN: Same Continent KeyRR with SH (+75%)

TRADE ROUTE REPLACEMENTS:
Once a city has 3 Trade Routes a new delivery may replace one of the existing routes. If a route already exists to the Destination city, the commodity listed will be changed to the newer commodity. If a route to the Destination city does not exist, the computer compares the Base Trade values of all existing plus new Destination cities and keeps the routes to the cities with the three highest values. Multipliers are ignored in comparing Trade Routes for replacement. To keep from replacing an existing Trade Route with higher multipliers (such as replacing a TR to AI city with one to domestic city), lower the Base Trade value of the new city below the values of existing cities (of course, this will lower the Bonus Payment amount some, but if the Destination city is the SSC/STC with over 100 trade arrows the difference may be small). Rule of Thumb for trade arrows in AI cities is 1 per citizen in Desp/Mon/Commy/Fundy, 1.5 in Rep/Dem.


HELP! - I need help checking these formulas. First of all, I cannot find any Corruption Loss formulas that differentiate between Base Trade and Trade Routes. SlowThinker's thread on Corruption lumps it all together, but my testing indicates there are two factors involved. Secondly, I don't have enough testing to prove the order of multipliers and the additive nature of the Transportation multiplier - I just took that from Samson's thread. I need players to apply these formulas as specified in their own games and post here any anomalies.

Please post save games with a description of the deviation issue being challenged. "I'm pretty sure..." will not be accepted.

Last edited by Elephant on 28-04-2004 at 02:58

	22-04-2004 03:47									#2
	Suffering from ads?

Good work, Elephant.

You may want to consider adding a parenthetical comment at the end of the first paragraph of the "Trade Route Repalcement" section. It may not be obvious to some that ...(lowering the base trade of the new destination city will cause a lower cash/science delivery bonus.)

Monk

	22-04-2004 18:02									#3
	Support Apolyton, buy Civilization 2

I must confess that this is a technical aspect of Civ that has never really turned me on - I simply hang onto the 'Rules of Thumb' ...
However, one thing I seem to get confused - is this a formula for the trade bonus - or for the ongoing trade route gain - I believe the latter - but this should be made clear

Great work Ellie

Stu

	22-04-2004 19:08									#4
	Support Apolyton buy from Amazon

Monk: so added.

Stu, I'm working on the on-going Trade Routes, not the Delivery Bonus. I don't think anyone could improve Samson's thread. Sorry it's not very "sexy", but I thought we needed a separate thread to bring together what several players had commented on in other threads. Should make it easier for reference by new players. I'll tweak the first post as modifications are confirmed.

	23-04-2004 02:51									#5
	Help yourself to an AD-FREE life

Good work, Elephant, a thread like this one was always missing.

Did you go through 'Links' thread (link in GL)? I remember one or two older threads that were focused on the ongoing bonus too.

What about to concentrace here also links to interesting threads about this topic?

quote: Base Trade Modifiers: - (-1) in Despotism for each tile that has >2 trade arrows - (+1) for each road on Grass/Plains/Desert tiles - (+1) for each road on other tiles with >0 arrows ("special" tiles or rivered) - (+1) in Rep, Dem, or Celeb-King/-Commy/-Fundy for each tile >0 arrows - (+1) for Colossus for each tile >0 arrows - (x1.5) with SuperHighways for each land tile >0 arrows with road/railroad

This is valid not only for caravan, but it is a general city economics rule, and so it should be separated from

quote: - (x???) Base Trade Corruption Loss

BTW, the order is important: a question about the relation between the terrain and a road built on it

	26-04-2004 07:29									#6
	Support Apolyton, buy Civilization 2

Yes, I did try to list the Modifiers in the right order.

I'll take any suggestions for links and post them in a "followup" section at the bottom of the first post.

ST, you did some statistical analysis on Corruption loss a few years ago; care to redo that to try to separate the Basic corruption from the Trade Routes?

	28-04-2004 01:19									#7
	Increase Your PM Length

Is the Superhighway bonus ONLY for land tiles with arrows, or will it apply with ANY tile with arrows???

Iirc I thought I saw justification for those one tile isles (I know, I know, it doesn't make sense but if the gain is there...)

	28-04-2004 02:46									#8
	Put an end to popups!

The SuperHighways Modifier is for any land tiles with Roads. Does not apply to water tiles. The SH Multiplier applies to the TR value calculated by the Basic Formula (without remainders).

	28-04-2004 03:01									#9
	Support Apolyton, buy Galactic Civilizations: Deluxe Edition

Perhaps I don't get all the details but I think a rough way to look at Superhighways is to look before and after. Land tiles, with roads, get an extra arrow; sea tiles do not. But, it also seems that trade routes values go up ~ 50%. One is total trade arrows while the other is arrows from trade routes.

For this reason, a city with sea specials, which would yield some nice trade routes, but only a few land tiles, will benifit from superhighways. The extra land based arrows plus the extra trade route arrows give a nice boost to potential gold or science, depending on the slider choices.

Monk

	28-04-2004 19:27									#10
	Full PM-box? Change here!

Yes, a city on a single land island tile will see it's Trade Routes increase 50% with SuperHighways, but only the land tile the city is on will get an extra trade arrow (assuming it was built on Grass or Plains; if it was built on Wine or Spice it would get 3).

	29-04-2004 00:06									#11
	Got spare money?

OK -- that jives with what I recalled -- same number of arrows per sea space, but the trade routes jumped.

(Found it somewhat worthwhile in Cfc GOTM 37, where money was no object.)