The Galactic Map - Newbie Questions

[Havan_IronOak (OP)]

I'm working on updating the Wiki section on the Galactic map and I've got couple of questions that I'm hoping someone can answer for me...

1) What does it means when there's no center green circle for a system? I've not encountered this in-game myself but I've seen it in Let's Plays and in other Galactic map images.

2) The ship icon in the upper right indicates that your empire has at least one ship in that system, correct? What does an icon in the lower left indicate?

3) What exactly qualifies a planet to be included in the planetary numbers in the center of the system circle?
e.g In Sol (My starting system) I have my Home world of Earth and Colonies on Mars and Luna I'm seeing a Blue Circle with a 1 and an orange circle with a 2
      In Luyten I've declared colonies on 5 bodies (all with zero population so far) I'm seeing a Blue circle with a 1 (I'm guessing that's due to 1 Terrestrial Planet (and a ruin) with a colony cost of 0.32)
      In Barnard's Star I've declared colonies on all 6 bodies (all with zero population so far)  with any planetary colony suitability (Two of them are below 3) yet there is NO Blue Circle in the center of that     system on the Galactic map. What's the difference between this and Luyten?

[Rich.h]

The empty circle could be either a black hole system or a nebula system though I could well be wrong there.

The ship Icon denotes that you have a TG in the system, it does not however indicate anything about actual ships (so for example a PDC TG would still show). The lower left icon appears if you have the option to show shipyards checked, and obviously it denotes you have one or more shipyards in that system.

As far as the planet numbers go it depends on how you play with the map settings, there are options to show for example planets between 2-2.9 colony cost. Or others that have different costs. In addition there are option to show planets you have a colony on, or planets with >100m population. If you look through the list in the galactic map you will see all the variations you can apply to show or hide planets & colonies.

[Erik L]

I believe the empty circle is a bodiless system. Just the stars.

[Haji]

I have to agree with Erik and disagree with Rich.h. An empty circle is a system without any planets or asteroids, but I think you can have comets in them. I may be wrong, you'll have to play with your galactic settings yourself to check this out.
Rich.h pretty much also gave an exhausting answer to the third question, but the quick version - the number of planets showed and represented by a deep blue dot is number of planets with colonization cost below 2.00 assuming you have no colonization cost reduction technology researched. If my memory serves if you develop the first level of this technology, the dot will show you planets with cost below 1.90. The other options will be adjusted as well. Again it would be best if you checked that.

[Ferret]

Empty circle systems can have comets.

It's not nebula, nebula has a big purple background circle behind the systems.