Simple spatial ordering or TSP algorithms? I'm not sure if this is the right place to ask, but I suppose you'll tell me.

I'm writing a program that produces a series of points on a map, and I need to put the points in some linear order so that adjacent points in the list are usually near each other. I just want to tack this on as a minor feature, so I need a simple algorithm that won't be hard to implement, and won't take more than O(N2) time.

I don't need much accuracy so maybe Z-order or Hilbert order would suffice, but the points are floating-point, and I only know how to implement Z-order for integer coordinates.

So, what algorithm would you suggest?
A relatively simple way of implementing this would be to simply divide your map recursively into a quad-tree until every node of the quad-tree is either empty or contains at most one point.

Now simply apply your Z-ordering to the nodes of the quad-tree.