Quote Originally Posted by icosahedron View Post
Any other attempt at relating 3D space to a 2D map is probably doomed to failure.
I would say that it depends on the scale that you are representing. Displaying an entire spiral galaxy should not be a problem since they are generally fairly flat and wide. So if you are looking down from galactic north you would see a disc that is something like 100,000 light years in diameter and only 1,000 light years in depth. (a ratio of 1:100) So you could conceivably notate stars of interest with their distance from the galactic ecliptic (positive or negative) if you needed to, but otherwise the depth that the star is at is not really as important at this scale as its distance from the galactic center.

However if you are trying to represent a cubic area of space, then yeah, you run into a lot of problems trying to display a field that is just as deep as it is wide.