Trade represents income generated by ships equipped with trade modules, such as freighters. In order to establish a trade route, a trade module equipped ship must move to a planet belonging to another civilization. The value of the trade route is proportional to the length of the route, as well as the population of both the destination and home planet of the trade ship. Once the trade ship reaches the destination planet, the trade route will be established (represented by a faint trail on the main map and a tiny trade ship traveling on it 1 square per game turn), and both civilizations will start receiving the same base amount of trade income. The base income returned each turn by the route is about proportional to the time the trade ship is en-route, modified by civilization's trade bonuses. When the tiny trade ship returns to its starting planet is the value of trade route reset to its starting value, and tiny trade ship starts another round. Trade ships are able to be attacked, so they should either be protected or only allowed to operate in safe areas of space. Civilizations can only have a limited number of trade routes, a number that can be affected by technology, racial bonuses, and United Planets votes. The trade tab of the Domestic Policy screen lists your civilization's current trade routes as well as their average income. This is also where the maximum number of trade routes for your civilization can be found. This screen can be used to discontinue trade routes if necessary. In order to utilize trade modules your civilization must first research the trade technology.
- sourced from article "Trading" by Nealdt
Trading profits may be increased by building Economic starbases with the trade route in range. Upgrades to the starbase may increase profits by any trade freighters passing through.
Trading with other civilizations will improve relations with them. If trying to make an ally or staving off war, create at least one trade route with them.
The Galactic Privateer project will protect freighters from attack, allowing them to travel through warzones unscathed.
You can have more than one trade route with the same planet.
When your treasury increases over 10,000 BC, trade revenue decreases to 50%. Valid for all versions of DL, and DA up to current 1.6.