[ ] Do we just want to convert from the other coordinate system to geographic coordinates? Or should we support other coordinate systems natively? As long as on earth, it seems plausible to require a transformation from local to geographic.
[ ] How do we expose Z? Local coordinate systems probably have a fairly precise Z value. I guess we could define it relative to the building, but that's also making some assumptions like there being a single reference. Could get complicated.
Anyways, not stuff we need to solve today. I expect indoor navigation might be an interesting domain in the future though so something to keep in the back of our heads.
This would support certain types of indoor positioning that deal in other coordinate systems like XYZ.