Thanks for the information. I've seen the articles/illustrated examples on soasewiki.com, and while they do provide a great breadth of information on the trading system, they still leave me with one question: what conditions govern the behavior of the trade line? Essentially, how does it decide to connect to the next trade port, and how does it decide on a path?

I have observed that the line does not always continue on to the next trade port, even in my most simple tests. When attempting to construct a more or less linear trade line through adjacent planets, I reached a point where the line did not continue on to the next trade point in the line. It didn't even require a jump through a UCGW. (In this line I had one UCGW jump earlier in the line, but all other segments were between adjacent planets.) I haven't been able to figure out what conditions would make the line continue through the other trade ports, but stop expanding at a certain one though I continued with an identical pattern of construction.

Also, in this particular test, I think the planet at which it stopped only had two phase lanes, one into it along the path of the trade lane, and one out of it to the next planet where I placed a trade port. This makes me curious about what happens when more complexity is introduced. What if a planet has several phase lanes and you place trade ports at more than one adjacent planet (other than the previous trade port leading "into" the planet)? A fork in the road. How is it determined which path the trade line will take? Or does the line simply end when it has more than one place to go?

As far as the build order of the trade ports, I think (I'll have to confirm this) when I scuttled the first trade port, the starting point of the trade line moved to the second trade port I built, and so on. This may be coincidence, due to the linear nature of a large part of my tests, but I still think the trade line originates at the oldest trade port.

I haven't been able to draw many conclusions from my observations. The line seems to behave almost counter-intuitively. But I think that this information could be useful, especially in large maps where this kind of planning is needed to ensure economic efficiency.

I just tried a few more things and encountered two instances where the trade line does not involve the planet with the first trade port. In the first, the first segment of the trade line is sometimes dropped to prevent the completion of a loop. In the second, I created a trade line five or six planets long and then placed one trade port on each planet on the map. The final trade line did not pass through any of the first six trade ports I built. This would imply that none of the conjectures I've made about build order are true. But, I did see that sometimes the trade line takes a "path of least resistance" and sometimes it goes the long way around depending on the order in which the trade ports in the area were built. Sometimes the line will select the longest possible route on the map, and sometimes it will select the most efficient route beginning with the first trade port. Perhaps some parts of it are random? There doesn't seem to be a logical way that it works.

Forgive my ignorance, I'm new to these forums, but who is Blair?

i dont understand why a dead asteroid will break the line

its not my fault they dont have logistic slots!

Blair and Craig Fraser are the two founders of Ironclad games (they are brothers, not spouses haha). 

It's good to hear that it's getting changed. I guess that means I can stop trying to figure it out. Thanks for the information.

As Annatar said, this is being completely changed for Entrenchment, so I wouldn't bother banging your head to understand it. We admit its too complicated and confusing in the original Sins.

However, the trade system changes are NOT in Entrenchment beta 1 as they are related to something else we are mucking about on.

sounds like beta 1 is complete?

OH SNAP 

It chooses the longest "shortest-path" between worlds, crossing only UCGWs and trade ports.  If that doesn't make any sense, well that's why nobody tries to explain it.

So for a concrete example, let's take a trade route currently going from A to B.  Now, at C you build a port.  However, A, B, and C form a triangle (there's a phase lane from A to B, one from B to C, and one from A to C) so the shortest path between any two of those gravwells will always be 1 and your trade route continues to only be from A to B.  Next you build one at D which only connects to C.  Now, the longest shortest path is 2 (between D and either A or B ) so your trade line will switch to either "A to C to D" or "B to C to D".