I may be wrong but we in astronomy have several sky indexing schemes, which
allows to effectively use classical btree index. See
http://www.sai.msu.su/~megera/oddmuse/index.cgi/SkyPixelization
for details. Sergei Koposov has developed Q3C contrib module for
PostgreSQL 8.1+ and we use it with billiard size astronomical catalogs.
Oleg
On Fri, 17 Mar 2006, Michael Fuhr wrote:
On Fri, Mar 17, 2006 at 11:41:11PM -0500, Tom Lane wrote:
Dan Harris <[EMAIL PROTECTED]> writes:
Furthermore, by doing so, I am tying my queries directly to
"postgres-isms". One of the long term goals of this project is to be
able to fairly transparently support any ANSI SQL-compliant back end
with the same code base.
Unfortunately, there isn't any portable or standard (not exactly the
same thing ;-)) SQL functionality for dealing gracefully with
two-dimensional searches, which is what your lat/long queries are.
The OpenGIS Simple Features Specification[1] is a step in that
direction, no? PostGIS[2], MySQL[3], and Oracle Spatial[4] implement
to varying degrees. With PostGIS you do have to add non-standard
operators to a query's predicate to benefit from GiST indexes on
spatial columns, but the rest of the query can be straight out of
the SQL and OGC standards.
[1] http://www.opengeospatial.org/docs/99-049.pdf
[2] http://www.postgis.org/
[3] http://dev.mysql.com/doc/refman/5.0/en/spatial-extensions.html
[4] http://www.oracle.com/technology/products/spatial/index.html
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83
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