The point being that an orbital map is a bit special, so it would be easier for the MapStructure side of things to only accept a vector with lat/lon tuples and plot a corresponding line/curve.
Then what do I need the map structure for? That's just a plot on a background raster image (which I have right now).
Point being - it'd be interesting if it'd be somehow
less effort - but if I have to do the same computations anyway, it ends up being more effort that way.
I guess that's the common thread in recent conversations. The Shuttle contains plenty of trail-blazing stuff that
could be of interest for others (a shitload of coordinate transformation routines for both Nasal and JSBSIm, a general thermal modeling code, numerical fit routines, new and improved geodesic computations, the blackbody radiation shader, the procedural HUD code,...) and pretty much after every Shuttle milestone release I summarize what's there on the mailing list and ask if anyone is interested.
So far, we've got few takers for the graphics stuff (the thruster flame, the HUD effect,...), not so much for the rest (not even for the parachute code which is available and well-documented).
Usually what this requires is someone stepping up and willing to at least share the workload of implementing this more widely - and documenting it. I'm not interested in investing work to generalize these code pieces, make them more widely available and write Wiki pages just on the off-chance that someone might have use for them - I have the code, it works for me, I try to get the information out that it's there, if anyone has use for it, ball is in that person's court.
So if you want to add orbital functions to the map layer, I'll be happy to tell you where the calculations are done, and I'll tell you what is there for what reason and I'll handle any commits to FGData, but I'm not investing any work.
there is one on the craft, itself so you can see what areas could view the craft flying over and one at the viewing location site so it can tell when the craft comes into view
There actually is no such display anywhere among the Shuttle avionics pages. There isn't even a summary display of orbital elements, in fact the orbital information you do get from the avionics is scattered across three different pages.
Otherwise, it's not so much for visibility but for communication line-of-sight (which was more essential before the TDRS network which gives you an uplink to a satellite in geosync orbit). We internally have the line of sight information producing a local horizon distance from the S-band antenna code.