> There is also some possibility to discuss what it means for one
> point to be bigger than another.

It must be application dependent. For example say you are writing an
application which represents information about coordinate systems for
multiple different graphics models. Some of those models may have Y
increasing bottom to top, others top to bottom. So in one case a
larger Y indicates potentially a "smaller" point!

Of course this would be true even if you were ordering the points in
two dimensions, like a quad tree.

-- 
Patrick Logan                 mailto:patrickl at gemstone.com
Voice 503-533-3365            Fax   503-629-8556
Gemstone Systems, Inc         http://www.gemstone.com