The idea of these in game icons would be help players move easily across distances, from large to small scale. They could be placed at any of the corners of the screen (default bottom right) and offer the player a quick option to jump to a specific scale. Another possibility is that this could also be used to alert the player to events or attacks going on at that particular scale. For instance a galaxy event would be a enemy commander or player being taken out. The player would then see a red flashing galaxy icon that when clicked would direct them to the incident. There is also the possibility of colour coding the flash to distinguish between ally needs or other critical game info that is occurring, such as asteroid launches. The icon would come pre-loaded with a set scale, but could easily be edited by the played to create a custom one. I think it also meets the requirement of being fairly minimalist way for relaying information. This is obviously pretty rough but I think you get the general idea. If there is anything else like this please msg or link ideas you might mesh with this one.
Judging by the zoom levels you propose, I suggest reading up on the Galactic War. You'll never zoom beyond one system.
The tech to simulate an entire galaxy of RTS games on a decent PC doesn't exist yet, sorry. Try again in roughly four years when quantum computing becomes more affordable.
Your levels should be adjusted. Surface < Planet < Satellites < System Where Surface will be the zoom level you use the most (looking at your units). Planet will view the entire planet / moon / asteroid you are currently on / have selected Satellites (for lack of better word here) will be the planet and its local moons / satellites (orbitees) of the planet / moon / asteroid you are currently on / have selected System will be the whole play field. Surface Icon: reprehensive of a continent, perhaps a half sphere Planet Icon: Small Sphere Satellites Icon: Small Sphere with 1 or 2 spheres around it with a drawn path System Icon: Sun Sphere with 1 or 2 planet icons. Clicking on the icon will to that zoom. As well a hotkey would be nice, something like Ctrl-Mouse Wheel to scroll between the different zoom levels. The other zoom option would be interesting for galactic war map, however that will work.
