Thanks to all who offered support. After looking at the Berkeley paper on
R-trees, I've determined that it's exactly what I'm looking for. In fact, it
has been suggested that I contribute to PostgreSQL by modifying rtree_gist to
support circles. I've decided to not only do this, but also try to include
support for spherical sections. This will enable exact radius searches
anywhere on a sphere (e.g. a distance around London that includes Tokyo). The
project I'm working on has desires to go international, so this will
ultimately be useful to us.
--
Milo Hyson
CyberLife Labs, LLC
