Glad to see more graphics work being done in Go. This is built on `pinhole`, which is built on `gg`, a 2D rendering library that I wrote. How many layers deep can we get? :)
gg and pinhole made this easy to write. The globe package really just deals with mapping (lat, lng) space to cartestian coordinates (and also includes some land/country datasets).
This may or may not be useful, but here's a Go package containing a bunch of city data. It might be a good fit for people using your project.
https://github.com/mmcloughlin/globe/blob/master/examples/ci...
In fact I might switch it, since the cities json file I used has some oddities.
Layers, visualized:
https://godoc.org/github.com/mmcloughlin/globe?import-graph&...
Keep it up!