# Hyperbolic coordinates

You can uniquely specify any point in 2D Euclidian space using 2 numbers: the distance from the infinitely long X-axis, and the distance from the infinitely long Y-axis.

How do you uniquely specify a point in 2D hyperbolic space? Can you do it with just 2 numbers? Can you do it in a "uniform" way? How would that work?

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You did not ask about adding coordinates in your OP. If you need an analogy to the distance description, then this can be achieved -- eg in the disc model -- using the inteersection of the disc with the Euclidean $x$ and $y$ axis and then use geodesic distance. ($x$ and $y$ axis are geodesics in that model). –  user20266 Jun 1 '12 at 13:29