I haven’t seen this posted anywhere else and thought it may be of interest to some.

I wanted to optimize the placement of my starbases so that they covered as many of my planets as possible. I was uncertain of how the circular influence area of a starbase mapped onto the square grid pattern of the map, so I went to the trouble of creating starbases at various locations and then checking planet details to see if it received the starbase’s influence. In doing so I came up with the following map of a starbase’s influence area.

The green circle is the area of influence shown when you select the starbase (I think the area shown by the constructor prior to creating the starbase has a radius of one parsec less). Any planet within the red polygon will be in the starbases influence area. Conversly, assuming a planet at the center, any starbase built within the red polygon will have influence on the planet. The basic gist of this is that if a planet is in a square that is even partially covered by the starbase’s circular influence area then it’s covered.