Re: New PostgreSQL type, RADEC

[Peter Mount <peter@retep.org.uk>]

On Sat, 7 Jun 2003, Robert Creager wrote:

> To be able to use the R-Tree index, the following operators are
> considered:
> 1. << and >> (left of and right of - think points)
> 2. &< and >& (overlaps to left and overlaps to right - think circles)
> 3. @         (contained or on - think point contained or on circle )
> 4. &&        (overlaps - think circles)
> 5. =~        (same as)
>
> So, I believe that the main one we will want to use is 3.
> 1 and 2 would be interesting to define, and I'm thinking left if RA
> distance is < 0 and right if > 0 (the distance would always be < abs(
> 180 ) ). But, would anyone see any use for these, or any of them (other
> than 3)?

I think that #1 & #2 would be useful, 1 more so - not too sure how useful
#2 would be, but it's early in the morning :-)

I don't see much use for 4, while the only thing I can see for 5 is for
matching possible duplicate entries for an object, but then 3 would
possibly be better, because you could then include a degree of error in
the comparison - ie the object is within +-5" etc.

> Fishing for comments, before I write too much :-)

Always a good idea, as someone may have already done this...

Peter


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Peter Mount
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