Investigation of Trade Income

[therother]

Whilst compiling the Forum Index, I've noticed that there isn't really one good thread where we discuss all the facets of trade (or if there is, I haven't yet found it). So I hope that we can collate all our experiments, observations, and data here.

This first post is a placeholder for the summary of our investigations, to be written when we have some. Which is why this post does not say very much of use!

Will post -- or in some cases repost -- some data and observations in a bit.

[therother]

Okay, first real post. I'm going to try to sketch out where research currently stands. As always, corrects/additions gratefully received, although I'd like this to remain on topic as much as possible.

Some of this information (and theories) presented here are mine, but much of the credit goes to Quietus and Tamur, along with various other contributors.

There are some basic comments that can be said, with some reliability, about trade income. This is not exhaustive; I'm just trying to lay some foundations.

The basic trade good values can be found in the RTW/data/descr_sm_resources.txt file. From basic editing of this file, and looking at Sparta, which has no goods to trade, it can be see that there is a minimum value for trading.


Land Trading

Land trading is automatically established, via the road system, between neighbouring settlements. For trade to occur between settlements, they must have a common land border. Improving these routes past normal roads will increase income.

• The first level of roads adds nothing to land trade.
• Paved roads always doubles land trade,
• Highway increases it by a further 50%

So if you have a land trade route worth 100 Denarii with no roads, with will be worth:

Dirt	Roads	Paved	High
100	100	200	300

Improving the trading buildings will also increase this income.

Sea Exports

Sea exports are very likely to where you make the serious money needed to produce and maintain sizeable armies of high quality troops, and are therefore are crucial to a successful campaign.

The factors that I believe contribute to exporting (and hence importing) income are:

• Diplomatic relations between settlements - definitely trade agreements, and perhaps if they are in foreign (but friendly) hands.
• Resources the exporting city has to trade - the more resources, the better; the greater the intrinsic value of each resource, the better.
• Resources the importing city already has - you can't trade a resource a settlement already has.
• The distance (via sea) between settlements - the shorter the better.
• Population of exporting city - the higher the better.
• Buildings in the exporting settlement.
• The traits and retinue of the Governor.

You don't need trading resources to be able to trade. See Sparta, for example.

Factors that I believe restrict export markets:

• Diplomatic relations - you can't trade with a faction you are at war with.
• The distance (via sea) between the settlements - there seems to be a certain locality outwith of which you can't trade by sea.

Sea Imports
The value of any given sea import is solely dependent on the region exporting - local buildings, governors pay no part. It is always 20% of the value of the route to the exporting city.

How export/import routes are chosen is an open question. Which is to say the exact factors (and their influence) that determine the value of a route are as yet unknown. We do know that the game will always select the most profitable export routes. Factors such as the length of the trade route, trade agreements, locally available trade goods and population of the settlements in question seem to play a role.


Open Questions

1. How are export routes chosen: in other words, we want to know the factors involved in calculating their value, and the exactly contribution of each of these factors.
2. What do trade buildings, such as the trader line, actually do to improve trade routes?
3. What do cities, with no resources of their own, trade with other settlements?
4. What are the geographic effects on trade?
5. ???

[Szun]

well you mentioned sparta, I bet it has hidden resources in the region file that doesnt show in game but you see the tradeincome.
You can even have gold hidden and can build mines without the map showing it.
Its a bit wierd tho, not knowing what resources that settlement has.

[therother]

well you mentioned sparta, I bet it has hidden resources in the region file that doesnt show in game but you see the tradeincome.

Well, AFAICT, Sparta has only the hidden resources of sparta which allow it to train the Spartan Hoplites. But you may be right.

I have, however, edited my descr_sm_resources.txt so that all resources are now at 0 value (like camels are) and are therefore not traded. Every settlement in the game, that I've seen, is still trading, albeit at a lower level.

Now, using this base trading setup, I've been able to determine that the value of land trade income is the same for each partner, all other things being equal (i.e. goods traded, roads, trading buildings, governors, etc.)

Also the value of the route, as the two locations are fixed, is dependent of the combined populations of the settlements i.e. the income will be the same if the aggregate population is 30,000, whether this is split evenly, or 28000/2000.

The third observation is that distance doesn't seem to be a factor for land trade.

For instance, the 3 settlements on Sicily (Messana, Syracuse, and Lilybaeum), all have populations ~20,800. The income for the Messana-Syracuse route is 54 each, which is the same for the Messana-Lilybaeum route, despite being measurably further away.

Edit: The first trader building seems to add 10% to the trading income from land trade (the local settlement only), and 10% to all exporting routes. A further 10% was added for each increased level.

Example:

None	Trader	Market	Agora	G.Agora	MerQuart
347	381	416	451	485	520
267	294	321	348	374	401
%	9.8	19.9	30.0	39.8	49.9
%	10.1	20.2	30.3	40.1	50.2

Oh, and building a dockyard had no effect on the value of these routes. It just added another route.

[HopAlongBunny]

Excellent thread.

Will this be moved or stickied in the "Guides" section?

[therother]

Will this be moved or stickied in the "Guides" section?

Probably neither. I would imagine it will be moved to the new research sub-forum when it gets created. See here for more info on the proposed forum.

[Szun]

Laconia
Sparta
macedon
Helots
244 13 24
sparta, dogs, pigs
5
7

this is the sparta entry in region.txt in vanilla game..no tradegoods..
dogs and pigs are only for building troops. Kinda odd that there is a export of goods..might be the town is exporting goods from a landtrade over sea trade...

[therother]

might be the town is exporting goods from a landtrade over sea trade...

Problem with that theory is that I made all tradable resources = 0 value, so that they were not traded at all (c.f. camels). Even then, there was still trading going on in all my cities. But I will get back to research on this matter soon, so hopefully a solution will present itself.

[therother]

Very minor update on the effects of distance on trade.

Land trade: the distance between the settlements is not a factor in determining the value of land routes.

Sea Trade: the distance between the two trading ports is what matters - the distance between settlements themselves is irrelevant. Edit: In fact, it seems that it's the actual trade route distance (the length of the dashed line) that matters, and not the straight-line distance between the ports. So land obstacles between ports will reduce trading income.

[Simetrical]

The first trader building seems to add 10% to the trading income from land trade (the local settlement only), and 10% to all exporting routes. A further 10% was added for each increased level.

Example:

None	Trader	Market	Agora	G.Agora	MerQuart
347	381	416	451	485	520
267	294	321	348	374	401
%	9.8	19.9	30.0	39.8	49.9
%	10.1	20.2	30.3	40.1	50.2

Is there any cap to this effect? What happens if you build a Pantheon to Mercury in addition to a Curia, for instance?

-Simetrical

[Quietus]

It seems that the population of the exporting city has some factor into the sea trade. But it doesn't fully account for it.

The higher the population, the higher the export. We really need to collect all the factors. What I meant are base factors not the tangible and upgradeable ones.

Try training queueing a peasant unit. Check the trade income. Queue another, then check. Each bulk of unit seemed to have a fixed effect on export income.

For example, I lose 3 denari trade export income for every 240 units I train in Rhodes. Since I can only queue about 9 units, I had to compute the rest. And it doesn't account for everything. Maybe, it is scaled.

Of course, the values differ for every region.

Laconia
Sparta
macedon
Helots
244 13 24
sparta, dogs, pigs
5
7

this is the sparta entry in region.txt in vanilla game..no tradegoods..
dogs and pigs are only for building troops. Kinda odd that there is a export of goods..might be the town is exporting goods from a landtrade over sea trade...

Will have to check this file out since I can't figure out the Resource.txt files.

[mfberg]

What effect on trade/trade income do the rebel/enemy units on your roads have? Do they block all trade between the connected cities? Can the trade re-route to bypass the blocking army?

mfberg

[Quietus]

Hi mfberg,

There are values I've posted in the Economics guide in the RTW guides section. They only partially block and no, there are no re-routes. All the more reason to get rid of those rebels quickly especially on rich provinces since it can affect both land and sea trades (not to mention the devastation on farm incomes).