Simulating Trade Routes

[Mark Oliva]

It's pretty clear to me what you want to do, but it's not at all clear to me what you want from us. You asked about an algorithm. A sensible algorithm would be pretty illusory, because the number of factors that affect trade and its success or failure are variable and often not logical but rather politically emotional. However, if you're going to implement the following basically good concept:

Each city supplies certain luxury or manufactured goods for export, such as alcohol (wine, rum, beer), weapons and armor, jewelry, textiles (wool, cotton, silk), perfume, dyes, spices, incense, glass, ceramics/porcelain, alchemical goods, furs, fine timber, opium, etc.

You should give more thought to what you can and can't export. In the 1300s to 1500s, beer, for instance, certainly was one of the items you wouldn't export. Beers and ales of that era spoiled within a few days' time. Not only was refrigeration limited to what a beer cellar could provide, but the use of effective ingredients - particularly hops - that stabilized and helped preserve the brew were little known.

[SteelyGlint]

I guess you're right, it's a little hard for me to explain what I'm looking for in responses here. I'm trying to figure out how the wealth produced by trade gets distributed, and what intentional human factors go into deciding where trade hubs appear. Is there a positive feedback loop caused by an arbitrary city having a slight edge in trade, and the benefits from that edge spiraling into local dominance? If so, how could I simulate that?

Why is it that some tiny states like Venice, Genoa, Holland, the ancient Phoenicians, and Lubeck (the seat of the Hanseatic League) were able to exert such extensive control over regional trade? Is it simply because they happen to have powerful navies, and therefore are able to protect their merchant fleets?

Would merchants work solely out of their "home city," trading only between it and foreign ports? Is that a good way to ensure that cities with the largest amount of merchants benefit the most from trade?

As far as I know hops were cultivated in central Germany by around 900 AD, and had spread throughout most of Europe as a beer additive by the end of the 1500's. But even if the cultivation of hops was a problem, I'd say it's a minor problem since this is an alternate world and I could say that beer production is more advanced than it was in the real world.