I was wondering how people generated star maps/galactic maps for their world, I've been struggling to find any tools.


  • 3
    $\begingroup$ Related: worldbuilding.stackexchange.com/q/23040/809 and worldbuilding.stackexchange.com/q/18718/809 $\endgroup$
    – Mołot
    Apr 21, 2017 at 11:49
  • 2
    $\begingroup$ In my opinion, star maps are a bad idea for a sci-fi setting. It is generally too hard both to represent a 3-d map on a 2-d page or screen. Its also hard for the readers to wrap their minds around it. Better to Just build a series of distances between planets, like a chart, and keep it proprietary to the author/worldbuilder. Use trigonometry every once in a while to ensure you don't make distances impossibly long or short. $\endgroup$
    – kingledion
    Apr 21, 2017 at 11:50
  • $\begingroup$ Welcome to WorldBuilding! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$
    – Secespitus
    Apr 21, 2017 at 11:51
  • 1
    $\begingroup$ A cool tool if you're just looking for ideas on planets or would like to explore a random chunk of space: spaceengine.org $\endgroup$
    – padleyj
    Apr 21, 2017 at 12:23
  • $\begingroup$ Used to make (very simple and schematic) sectors for the RPG Stars Without number : swn.emichron.com $\endgroup$ Apr 21, 2017 at 13:05

1 Answer 1


When I needed a map (for a game though) I wrote a little program that, based on a seed and some coordinates, generated me star systems on a grid. It would take in the seed as well as x,y,z coords and then generate a new system seed from that.

The grid size I choose was 1parsec³. Then some research on wikipedia on star density within our galaxy and based on that the chance for a star system with that cube.

Then I would also generate some planets orbiting the star(s). As for the star itself, I had a possibility for 1-4 stars in a system I think.

For each planet/star/astroid you can generate an id from 0 (star) to i (your last object) and generate new seeds.

This way you have a hand written seed from the beginning that generates more "random" numbers you can base further generation on. But since your seed + the coordinates form a grid cube seed and these create the next and so on you can with a single seed generate a universe that's always the same. It is also "endless" (until you get floating point or max int problems). You could also generate a very specifc zone of it on demand if you know the coords.

This way you can create an endless universe to use for whatever purpose. It's mostly data though and quite hard to make it into a human readable map. More of a "play area".

I for example like to use it as base for ideas. You could say "I live in cluster 000x000y000z and go 200 clusters on the x axis to 200x000y000z" and the program tells you:

You find a binary star system with 4 additional planets.

  • Planet 1: gas giant [additional generated stats]
  • Planet 2: rock planet (habitable zone) [additional generated stats]

Now you can base your story on that area. ;)

Should you want to use this as a basis for say a game or an interactive application it's nice to note, that you have to store the inital seed and nothing else, if you generate all information from it.

Textures as well as heightmaps can be generated from this too with fractal brownian motion or simplex noise/perlin noise. This might or might not be very useful depending on your case though.

  • $\begingroup$ Seems the best way to generate one randomly, would not look at all realistic though I would think, but then the distances involved would make a realistic one 'unrealistic' to produce. $\endgroup$
    – Kilisi
    Apr 21, 2017 at 13:05
  • $\begingroup$ That's true, it's endless as in "not a galaxy shaped universe". Making it realistic would be hard as the density of stars towards the center is higher and spirals have more stars too etc. Depending on your in universe tech however it takes forever to travel around and if you only view a small chunk it would still be okay as a setting. For galaxies you could think about running a mask (maybe generated too (; ) over the whole grid that prevents solar system generation in vast spaces between galaxies. $\endgroup$
    – Morfium
    Apr 21, 2017 at 13:09
  • 2
    $\begingroup$ Have you made this available somewhere? OP is looking for tools they could actually use... $\endgroup$
    – Azuaron
    Apr 21, 2017 at 13:44
  • $\begingroup$ For galaxies I've in the past done similar, with the tweak that the likelihood of a star existing in a parsec is non-linearly proportional to how close it is to the center of the galaxy. There is, of course, a black hole at the center. $\endgroup$
    – T.E.D.
    Apr 21, 2017 at 13:57
  • 1
    $\begingroup$ Tag software-recommendations means op wants a bit more than explanation. Sure, it could and should be stressed more in the actual body of the question, but still. $\endgroup$
    – Mołot
    Apr 22, 2017 at 7:59

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .