RE: R-tree indexing, RA wrap and LISTENing

[Chris Albertson <chrisalbertson90278@yahoo.com>]

> At what distance do you need the spherical operators over planar? 
> And would
> they be used often enough to justify their creation?  I don't believe
> they
> would be required for matching stars to each other (7 arcsec?).

If the pole or prime meridian runs through your data you
need a special opertor.  Either that or everyone using the
databse has to look out for those special cases.  IMO brtter to do
once in one place

Also if "7 arcsec is not exactly 7 secsec in both directions
and the same all over the sky then you will have location dependent
matching window size.  It s NOT an expensive operation because
firat you pre-fetc the stars with a bounding box then apply the
exact calulation only to the hits. 

=====
Chris Albertson
  Home:   310-376-1029  chrisalbertson90278@yahoo.com
  Cell:   310-990-7550
  Office: 310-336-5189  Christopher.J.Albertson@aero.org
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