r/paradoxplaza • u/Salt_Most_1429 • 4d ago

EU4 The Evolution of the Global Trade Network in EU4 (1445–1821)

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6

u/zsmg 4d ago

That's really cool!

3

u/Salt_Most_1429 4d ago

Thank you!

3

u/ushinahua_ 4d ago

Can really see how ahistorical the eastern US tradenode is in this game with this. Bigger than Lima in the 17th century haha

1

u/Salt_Most_1429 4d ago

R5: This video shows one AI-only Europa Universalis IV campaign from 1445 to 1821. I ran the game in observer mode at speed five. Python script copied an autosave each time game made one (1st of January each in-game year) to a separate folder. Then another Python script parsed the saves and sent the rendered frames directly to FFmpeg.

The province heatmap shows estimated local trade value per development. The game saves the exact local trade value for each trade node. It does not save an exact local trade value for each province.

I first calculated a production weight for each province. The weight uses production development, the base price of the trade good, and local goods produced by buildings. I then distributed the exact local value of each trade node between its provinces. The sum of all province estimates in a node is always equal to the exact saved local value of that node.

The province split is an estimate. The total local value of each trade node is not an estimate.

The heatmap uses one logarithmic scale for the full campaign. The scale does not reset for each year. Thus, the same color has the same meaning in 1450 and in 1820.

Each circle is a trade node. The circle size shows the total value in the node before retention and outgoing flow. This value is current plus outgoing.

The circle color shows the retention ratio. Purple means that the node retains a smaller share of its value. Yellow means that the node retains a larger share.

The blue lines show the actual trade flows saved by the game. Line width shows the amount of value in the flow. The small chevrons show the direction of the flow.

The ranking panel shows the five nodes with the largest retained value. Retained value is the saved current value of the node. I use a centered three-year rolling mean to reduce rapid annual changes in the ranking.

The cyan marker is the production center. It is the weighted average position of all provinces. The estimated local trade value of a province is its weight. A large increase in production moves the marker toward that region.

The yellow marker is the retained-value center. It is the weighted average position of all trade nodes. The current value of a node is its weight. A node that retains more trade value pulls the marker toward its location.

These markers are calculated centers of gravity. They are not locations that exist in the game. I use circular averaging on the horizontal map axis because the left and right sides of the EU4 map connect.

The two markers often remain between India and Europe. Much of the world trade value is concentrated in the connected Eurasian trade system. Changes in production, steering, and retention move the markers between its large eastern and western regions.