[postgis-devel] PATCH: New positional operators based on Y position of bounding boxes

[strk at refractions.net]

Happy New Year Mark!
That's Good Stuff to me.
Just... can vv &v ^^ &^ be used as operator names ?
--strk;

On Tue, Jan 11, 2005 at 11:11:58AM -0000, Mark Cave-Ayland wrote:
> Happy New Year everyone! :)
> 
> Here is a patch against CVS that addresses a slightly strange omission from
> the operators included with PostGIS. One of our import scripts had
> accidentally created some geometries with very large Y coordinates (e.g.
> POINT(0 1E20)) and in order to delete these rows, I had to select
> geometeries above a certain Y-coordinate which is currently not implemented
> in PostGIS as an indexable operator (I gave up waiting for over half an hour
> for a SELECT... ORDER BY... to complete on a multi-million row table,
> whereas it is already possible to do this in seconds on the X-axis using the
> << and >> operators).
> 
> This patch implements the following additional operators for PostGIS, with
> the ability to use a GiST index where one exists: 
> 
> 	A <<| B
> 		The bounding box of A is strictly below the bounding box of
> B
> 
> 	A &<| B
> 		The bounding box of A vertically overlaps or is below the
> bounding box of B	
> 
> 	A |>> B
> 		The bounding box of A is strictly above the bounding box of
> B
> 
> 	A |>& B
> 		The bounding box of A vertically overlaps or is above the
> bounding box of B
> 
> (to make sense of these operators, it may help to tilt your head 90 degrees
> to the right, where the | character represents the X-axis).
> 
> I've posted this for review instead of applying directly since I know Paul
> was considering reducing the number of operators included in PostGIS. I have
> done some simple tests using both sequential and index scans, and confirmed
> that the new operators return the expected results. Comments anyone?
> 
> 
> Kind regards,
> 
> Mark.
> 
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