A common set of coordinates here on Earth is longitude, latitude and elevation. The Prime Meridian and The Equator establish cartesian zero values. The conformally projected grid imposed on the surface of Earth can then be divided into bands of 6 degress (longitude) to project a series of 60 ellipsoids (pointed at each ends) which is the Universal Transverse Mercator. Measuring the distance from the Earth's centre is how we establish the geodetic height of any topographical location above the surface (although there is some ambiguity regarding the precise value of centre from country to country).
There is also the Galactic Coordinate System
which is a celestial system in spherical coordinates using the Sun as
the centre and the galactic plane or galactic equator to measure
positive and negative values relative to it. The fundamental plane was
defined by the International Astronomical Union
in 1958. Of course, we also have to allow for anisotropy in cosmic
microwave radiation to account for the alignment of galaxies rotating
on their axes as well as polarisation angles, but we are getting ahead
In the Star Trek
universe they don't use any of those coordinate systems. They use the
Grid, Quadrant, Block and Sector system to define the locations of
planets. So for example 43.89.26.05 represents the coordinates of Qo'noS
(or Kronos - homeworld of the Klingons). I think it used to be
09.68.27.70, but that was before the "alternate reality" where they
have portable transwarp beam devices to perform long-range
transportation across multiple lightyears. Really?
up 18.104.22.168 which is supposed to be the coordinates for Jupiter
(according to Khan - played by Benedict Cumberbatch in the movie Star Trek Into Darkness).
He speaks the numeric address beautifully, but if you look those values
up as an IP address, it is actually registered and hosted by Telus Communications
and refers to their geographic location in Canada, British Columbia,
Burnaby and you can even reverse lookup the postal code and phone
number . . . Latitude 49.250000, Longitude -122.949997. Yes, really.
I've got to disable the pause button on my Blu-ray player.