Right, seeing as we are now growing into a minor power with a small number of worlds, explaining how resources translate into wealth and power seems a good idea. Wealth is generated by Designated Economic Activites. A region (continent if you will) can support 2 DEA's. A planet can be made up of between 1 region (normally inhospitable balls of rock - Vespa...) to 12 regions (Gas giant, Jupiter). A planet also has moons with a size on the same scale. Habitable moons contribute to the possible population of a planet (So a gas giant with habitable moons can support a greater population than one with volcanic deathballs), but do not directly affect the total number of regions you can exploit through built facilites - this is hard coded and could not be modded. Number of regions and the habitability to the species at your disposal determine the population a world can support - small balls of rock supporting many billions are possible to some species. Some races like gas giants, and thier worlds can support trillions, making them formidable places to consider invading. Regions can be mountains, broken terrain or flat plains. Regions can range in fertility from alluvial to toxic, depending on habitability and your race - what is toxic for humans could be paradise for someone else. Regions can range in mineral richness from rich to very poor. Regions can also have specials that modify thier behaviour - rare minerals and suchlike. All these parameters can chage through terraforming. The properties of a region determine what DEA you should build there. Each DEA can have a massive number of addons and upgrades accessed through advancing your tech level, and the modding community has worked to expand and improve the original limited and dissapointing add ons. All DEA's emply individuals - people like having jobs. Not enough jobs can lead to unrest. In addition to DEA's there are whole planetary structures the provide a bonus to the planet they are found on. These can be upgraded to affect the entire system, or galactic regions as a whole.
Farming DEA's produce most food when built in fertile flat plains. Your farming output is modified by your race picks and your chosen form of government. Fertile worlds for your race tend to be found around stars of a similar age and with similar conditions to your homeworld, but can be found anywhere where the parameters are correct. Inorganic races need not worry about farming as they consume minerals. The higher your population, the more food you need to produce to feed them. Insufficient food can leave worlds starving, with obvious effects. If a world produces a food surplus, it can export food to a world with a defecit - either one of your own worlds or an allies. This produces trade income which feeds into your economy. The economy will be discussed in a later update.
Mining DEA's produce the most minerals when built in mineral rich hills. Inorganic races need to produce minerlas to eat. Mine output is also dependant on your race picks and your government. Mineral rich worlds tend to be found around younger stars formed from material released in supernovae. The minerals produced feed your industrial production - a lack of minerals slows all forms of production right down. Worlds with a surplus can trade thiers to mineral deficient worlds, also generating trade income. Selling surpuls minerals to a starving inorganic race can be pretty lucrative.
Industrial DEA's turn your minerals into useful output. Minerals go in, production points come out. More production points means faster ship and facility building. Some races use food as a raw material for industrial capacity. Playing as an organic tech race is challenging, as pushing production of a large number of fleets often leads to starvation and unrest. Some races have massive bonii to thier production and can be tricky to handle due to thier rate of production.
Research DEA's produce research points. More points means you unlock and develop techs at a faster rate as discussed previously. Some races are impossible to keep up with research wise - fortunatley these races are normally not very military minded.
Government DEA's generate income through taxation, and reduce unrest through the enforcement of the law. They tend not to offer much emplyment but do wonders for the efficiency of other DEA's.
Recreation DEA's are what you would expect - they reduce unrest sinifigantly, produce income based on how many tourists they attract, and can be developed into sites that attract people from all over your empire. They can cost early on before they turn a profit
Military DEA's are also straightforward. They are required before building military structures on a planet (such as missile bases, defense bunkers and so on). They have unrest reducing effects and provide bonuses depending on what structures are present to any ground troops during an invasion. Understanably they do not produce wealth and instead require funding.
The above image shows Earth's current planetary infrastructure tab - the Bioharvest DEA marked in red is being converted into a military DEA as for some reason one was not present on turn 0. Earth is exporting minerals and food to colonies (indicated by the green numbering in the summary panel), and due to having good infrastructure and a high population density is highly productive at this moment in time. In the lower half of the summary tab you can see that Earth is a size 6 (large terrestrial planet), with the moon being a size 3 body. This gives us 6 regions to exploit through built structures, and 9 regions that can support a human (or otherwise) population - the current maximum for our tech level is shown in billions (37). We have 17. A colony becomes signifigant when it has 1bn inhabitants.