Simulating Trade Routes

[SteelyGlint]

In my unprofessional opinion you need to develop a base cost for all materials that are to be traded. You then need to create a rating system to determine the base scarcity or abundance of the material for each province. Next would be the time scale for change either monthly or seasonal. Then you would have to create a chart for the events that could occur and the modifiers that they could apply to the product war, poor harvest, boom etc. Further more you would have to determine a base population for the provinces and the modifiers that could occur due to events plagues , war, economic expansion.

Yeah, this is essentially what I'm working on right now. I'm working on some quick dev tools to generate populations based on the environment surrounding each city. The amount of settled land within each province will be partially randomly generated, to account for unknown positive/negative events in the recent city history.

What are people's opinions about whether large cities in heavily populated provinces would increase or decrease the neighboring province density / major city size? Could prosperous neighbors cause higher settlement density but smaller major cities?

I'd assume that setting cheap food goods as the most basic economic unit would be a good idea. Perhaps 1 unit of food could be the food surplus generated by an average village (of around 200 people) for a given year. Obviously the quality of the harvest, tax levels, events like locust plagues or war, and so on would have an effect on how much food a given province produces per year. Anyway, this "food unit" would itself be equivalent to the ubiquitous gold piece used in so many settings.

The actual sale price of a unit of food would of course fluctuate, with 1 gp being the value in a good year, and the value skyrocketing in the case of famine or war. All other goods follow the same pattern locally, with base values that are adjusted by the ratio of goods in the province to the demand or consumption rate.

Anyway, another excuse for this post is to show the current state of what could be called an interactive map. The attached screenshots include a dev view of how cities are connected and an overlay that shows the connections in a more stylish way.

[Xyll]

Have you found this link on random kingdom generators? http://www.io.com/~sjohn/demog.htm

[Talroth]

I've been working on a similar economic simulation system (but as a tool for research.)

Where I started was establishing the diets of the time frame for the location to be simulated, and basically the economy get boiled down to "What does it take for me to survive?" as the key question every Agent in the sim asks.

From there I create a base where every person produces food, and only food, at realistic levels using the best estimates I can find. I branch out and start adding different food types, etc. Everyone should, in theory, be producing a decent surplus (Or are in an inhospitable environment and starving).

Then I start working on building the 'other' items, and keep adding them. Always keeping in mind how much a single human with the tools/technology in question could have produced. The really hard part is establishing guidelines on why people would want an item, and for this stage Maslow's hierarchy of needs is a great basis. Everything added is this assigned a point on a custom scale based on the Hierarchy of Needs and then the Agents go to town and begin trading with the goal to establish the highest points possible.

(Eventually I threw in a multipass trade function to seek a Nash equilibrium. Turns out we're all suppose to have high-end sports cars in Communism. Funny how the real world can differ so greatly from simulations.)

[SteelyGlint]

@Xyll - Yes, that's one of the resources I've been using, and it's where I got my ratio of cities:towns:villages.

@Talroth - Your method seems similar to mine, but I'm not sure I have the resources to simulate down to the individual agent... unless you refer to entire settlements as agents. I'm not even sure if I'll simulate anything below the city/town level, let alone individuals within villages. Village production will most likely be aggregated to keep things simple.

Your mention of the hierarchy of needs is a good idea. Obviously, the most needed category is food since I can assume that the cities were founded in places where water is available (though I can leave open the option of having lethal events that tamper with a settlement's water supply). The construction goods (clay->bricks, stone, wood) and associated industries (masons, carpenters) fill the need for shelter. I suppose the textile goods fill the need for shelter as well, especially in the northern region.

I'm thinking of introducing concepts like staple rights to make trade a little more interesting. Does anyone know of other interesting features of trade during the late medieval/early renaissance period?

[Talroth]

True, the scale of the 'Agent' in the simulation depends on the scale of the simulation as a whole. If you are doing a small village economy, then you can run it at a single person level and not bog down your system. Doing the whole world will require some scaling up to regional levels, which does make the Wants and Needs simulation a little more complex.

If I get some time I might rewrite some of the code this summer, and make it open source. Sadly I lack release rights on a handful of key components. (Biggest mistake I've ever made in coding personal projects.)

[Al. I. Cuza]

What did you use for those interactive maps?

[SteelyGlint]

What did you use for those interactive maps?

The program itself is mostly written by me. I used a 2D engine called HGE so I didn't have to reinvent the wheel, but all the rest was made from scratch in C++, Photoshop, and Illustrator.

[Al. I. Cuza]

Looks quite nice, really.

Here is something i wrote in another thread regarding trade:

Trade should be simulated by modeling supply and demand through simple factors, much like everything else. Every bigger settlement should have a base supply (anything produced in a small enough radius will be included). Every 1000 persons of each class should have a base demand, the percentage of classes in each settlement will determine the settlements' base demand. The amount of trade between 2 settlements could then be calculated as a function of profit and travel (anything from distance to travel method: the longer the distance, the higher the travel expenses, longer time wasted on the road, is there a road, is it paved, is there a means to use the ship or even train, etc...). It shouldn't be too problematic this way.

[SteelyGlint]

Wow, that's almost exactly what I was already planning to do. I even set base consumption to a number out of 1000.

I had originally wanted to do something that searched the trade network, but I recently decided that it would be much smarter/easier to simulate trade by running a multipass algorithm that is only concerned with single hops.

I have a number of factors that affect the consumption of each of my trade goods (there are currently 43), from prosperity to cultural proclivities. As you can imagine, certain goods are more elastic than others in their price/consumption rate.

[Al. I. Cuza]

I had originally wanted to do something that searched the trade network, but I recently decided that it would be much smarter/easier to simulate trade by running a multipass algorithm that is only concerned with single hops.

That would be even historicallz accurate. Most traders were forced by law to pass every market town in their way and offer their goods to be sold.

I have a number of factors that affect the consumption of each of my trade goods (there are currently 43), from prosperity to cultural proclivities. As you can imagine, certain goods are more elastic than others in their price/consumption rate.

Maybe you could post the results of your work until now (and I don't mean the programming). I could contribute better if I knew what you already have and it would benefit the whole forum as well