Red Hex = Unnav Space
Green Hex = Radiation Zone
Dark Gray = Unsurveyed space
Racial Color = Each race has been assigned a color for the hexes of their space. This has made it much easier to distinguish who is who on the map. This is so called "Open Space".
Light Gray Lines = Trade Routes. Again this has made it easier to determine ownership of space where a trade route crosses a border. (add and moving borders using line in Cyberboard is cumbersome)
Mines = The little box/chevron with a tail. The tail should point into a hex of the owning player. These are a legacy from U5 as the Andros can bypass these without issue. The Galactics just have higher priority things to do than remove obsolete minefields.
A large red number (1-5) in the middle of a hex: The countdown indicates a hex has been struck by an extra-galactic Andro weapons that appears to convert any hex into an Unnav hex. + - A hex with a "+" in it contains a minor system. They produce some income (and can be raided even if there isn't a trade route present) and with further investment can be upgraded into...
A system hex where the system symbol is black is a system owned by that empire. If it is green then the Andromedians have infested the system.
O - A hex with an "O" in it has a major system. These systems produce much more income than a minor system. Without a trade route, they produce as much as a minor system (but other rules that scale with major system counts treat them as a major system).
* - If there is a base in the Open Space hex, it will be shown with this symbol. Exactly what type of base it is you'll have to get near enough to figure out. These hexes may also be raided. Note that hidden bases do not show up on the map.
* in a red hex is a galactic power's base specially outfitted to survive in unnav space. These bases, if they are large enough, can be used to guide GP's forces movement via WORM tech to the other galaxies.
* in a white hex is a (redacted) base.
squiggle symbol in a red hex- these are even nastier forms of unnav space. The details of them are not widely known.
Bright Green hex- These are large radiation zones. They are not intense enough to be harmful to organic life, but they interfere with sensors, minefields, and cloaking devices. Small areas of the hex are not radiation zones and may have bases in them.
Solid line on a hex spine- A hex spine with a solid line along it is a border. These are rare in the Milky Way galaxy in U9.
Lines in the middle of a hex - This is a front line as two empires (or sides) slug it out. These are rare in U9.