How does TRADE work in the game?

[Foz]

Not really sure but iirc each city can trade with each other city if it wants to (only one-sided restrictions for the number of trade routes) so the game uses the cities that generate the most income to trade with.
Which factors influence that, I have no idea though.

Well, some of them are obvious at least: trade route distance and the value of the resource(s) involved both seem to affect the value of the trade route. I would speculate trade rights do too, though IIRC you can't have trade with a nation you don't have trade rights with, so this is difficult to test - what seems clear is that you get more benefit from routes to other faction's provinces, which is likely the effect of trade rights with that faction.

As for determining the routes you get, I imagine there is a maximum distance that a trade route is allowed to span. With that knowledge, the game can determine how much profit you'd make from trading with each province that is in range, and order the list by profitability. Then it could select the top N of them to establish trade with, where N is how many trade routes the current settlement is allowed. In reality the problem is probably a bit more complex than this to solve completely since full trade routes would presumably eat 1 available fleet from each end of the route. This means that a route from Rennes to London for instance might be among the most profitable for Rennes, while London may be able to do far better than that if trading with the Danes. In that case it may be beneficial to accept a lower trade route for Rennes in order to give London more routes to Danish settlements. So in reality the game probably generates all possible trade route networks for your nation, and then selects the optimal configuration, since a settlement-centered view can easily lead to a less-than-optimal solution. I realize it sounds like a lot of work, but to current processors this is more akin to counting on one hand than anything else really...

[nikolai1962]

This is how it works in RTW. I think it is the same in MTW2

First thing is the resources a region has. It can only trade a resource contained in it's region.

It will trade this resource with each adjacent land region the faction is not at war with who *don't* have that resource i.e two adjacent regions which both have iron won't trade it.. The base value is determined by the value of the resource and the population size of the recieving city. (I think it is just the recieving cities pop size that matters.) Dirt roads don't increase it but the higher level roads do. (In RTW the paved roads doubled the income from land trade IIRC.) Trade rights double the amount you get, markets etc add a percentage.

Sea trade works in a similar way. The different port buildings give you a number of export trade fleets. For each trade fleet you have you can have one export route. The game will look at the resources in your region (if any) and look for nearby (non-adjacent) regions that don't have that resource and calculate the most profitable one. The base value of the resource plus the shortness of the distance plus pop size of recieving city determines the value of the trade. Trade rights double it, markets etc add a percentage.

You also get a smaller amount from the trade of other cities exporting their resources to you.

[alpaca]

Foz: I think export only takes one of the fleets of the exporting cities, and trade routes aren't two-sided (so you can have cities that export to a city but not import from it and vice-versa). This would make sense because you can only export specific resources.

[Foz]

Foz: I think export only takes one of the fleets of the exporting cities, and trade routes aren't two-sided (so you can have cities that export to a city but not import from it and vice-versa). This would make sense because you can only export specific resources.

Is there no difference then between "export routes" and "trade fleets available?" The chart Sapi posted (by ArchieGremlin) says that the Port series gives the former, while the Merchant's Wharf series gives the latter. It's been my experience that building the Port series gives smaller boosts to trade (though still better than land usually) while the Merchant's Wharf series gives absolutely HUGE boosts to my sea trade. I was rolling with the assumption that they are in fact two different things.

In fact I would've said I think the following:

Export route - a single resource trade route, exported to the most profitable place. Agreed these are one-way. I'm not sure each is for one resource only, but that's been my impression.

Trade fleet - gives a full trade lane with another settlement, the two then exchanging all possible resources (i.e. every resource the other does not have). IMO this would be the only way to explain the massive numbers of resources I usually see being traded by sea on the trade details scroll - it's generally WAY more than how many exports I'd be allowed. It's not entirely clear if they go both ways.

So that's what I've been assuming is going on...

[alpaca]

Is there no difference then between "export routes" and "trade fleets available?" The chart Sapi posted (by ArchieGremlin) says that the Port series gives the former, while the Merchant's Wharf series gives the latter. It's been my experience that building the Port series gives smaller boosts to trade (though still better than land usually) while the Merchant's Wharf series gives absolutely HUGE boosts to my sea trade. I was rolling with the assumption that they are in fact two different things.

In fact I would've said I think the following:

Export route - a single resource trade route, exported to the most profitable place. Agreed these are one-way. I'm not sure each is for one resource only, but that's been my impression.

Trade fleet - gives a full trade lane with another settlement, the two then exchanging all possible resources (i.e. every resource the other does not have). IMO this would be the only way to explain the massive numbers of resources I usually see being traded by sea on the trade details scroll - it's generally WAY more than how many exports I'd be allowed. It's not entirely clear if they go both ways.

So that's what I've been assuming is going on...

Never heard of export routes to be honest, afaik (and can tell from edb) the port series simply increases the trade income for each route you have, the merchant wharfs add fleets.

[Foz]

Never heard of export routes to be honest, afaik (and can tell from edb) the port series simply increases the trade income for each route you have, the merchant wharfs add fleets.

Yeah it's not in the EDB, but definitely in the game. At the very start of the game, if you check a settlement right after you build a port for it to see what it's trading, it'll show some sea trade even though it obviously doesn't have any wharfs yet. In fact I doubt there's any wharfs anywhere in the world that could be trading with it, so that pretty much guarantees that some sort of sea trade "fleet" for lack of a better term is granted by the port. I'll see if I can figure out more about how the export routes (granted by ports) are different from trade fleets (granted by wharfs) tomorrow, if they are at all.

Note: I'm sticking with ArchieGermlin's naming conventions here for the sake of clarity, not because I'm set on them being correct. It just seems more simple to call whatever trade is granted by ports "export routes" and whatever is granted by wharfs "trade route." So, hopefully that will head off some potential confusion, and help keep everyone on the same page.

[alpaca]

Hmm there's indeed a bug, I just tested this a bit, and it appears that the trade fleets don't change anything (not even the value of trade routes), whereas the actual fleets you have at your disposal are linked to the port building.
I remember noticing it before, but I didn't play the game for a while ;)