Places are the smallest divisible unit of land or location of gameplay significance. They can take such forms as Surface Regions, Orbital Colonies, or even Floating Cities. Places generally indicate a location that can be inhabited or have some useful property that can be exploited. They may contain useful natural resources, advantageous local geography, or some other unique, location-specific feature. The characteristics of a Place are initially hidden from the player until they are revealed through a Geological Survey.
1.) Surface Regions - These are the Places that compose the surface of a celestial body. They have borders, never move, and are generally the least expensive to maintain (depending on the planetary environment and your available technology, of course).
2.) Orbital Colonies - These are Places that are constructed in orbit around celestial bodies. They are orbital vessels large enough to sustain their own local economy and can contribute to the overall system economy. As they are in orbit, their location is always changing, but predictable. Examples would be O'Neill Cylinders, Bernal Spheres, and Stanford Tori.
3.) Floating Cities - These Places are constructed on celestial bodies of which the atmosphere is so dense that a Floating City makes more sense to construct than a surface colony. Unless they are anchored to the surface, their location is subject to the underlying wind patterns of its host celestial body.
1.) Resource Presence - Perhaps the most common reason for establishing control over a Place. With the exception of Orbital Colonies, a Place can intrinsically contain any number and amount of common resources, and may rarely contain an exotic resource. Extraction and refinement of resources can form the backbone of a colony's economy and allow it to grow.
2.) Local Geography - Surface Regions can have a variety of terrain types that can aid or hamper its potential purpose. Mountainous terrain, for example, could be much easier to defend than Flat terrain, though it would likely be more difficult to build infrastructure. Floating Cities may be subject to varying levels of turbulence which present their own problems.
3.) Unique Features - Some Surface Regions may possess unique features such as Geothermal Springs (which could be useful for early settlement), Dust Storms (which would not be useful for early settlement), a Breathtaking View (which could boost its colony's migration and prestige), Ancient Ruins (on non-Solar worlds) and so on.
Each Place can connect to adjacent Places to form trade routes and build infrastructure improvements between one another. A Colony, for example, may build infrastructure between itself and a nearby resource deposit in order to establish a mining presence there. Ground troop movements take place through connecting Places. Surface Region Places and Orbital Colony Places are connected through the presence of a Launch System.