[postgis-devel] Should EMPTY be spatially equal to self ?

[Paragon Corporation]

> On Fri, Jan 13, 2012 at 09:53:31AM +0100, Sandro Santilli wrote:
> > On Thu, Jan 12, 2012 at 07:09:22PM -0500, Paragon Corporation wrote:
> 
> > > If you started with 1.4 your ~= meant bounding box 
> equality If you 
> > > started with a version prior to 1.4 and upgraded to 1.4+, your ~= 
> > > meant geometric equality
> > 
> > Well, now we are moving to 2.0 so a dump/reload is required 
> and we can 
> > feel free to assume the operator will be for everyone the 
> way we'll set it to be.
> > 
> > I think keeping ~= for bounding box equality is fine.
> > It's even mnemonically useful: "about equal".
> 
> Regina: I've seen your commit removing documentation of ~=.
> 
> Why so ? I've unleashed the operator use of GiST index this 
> morning making the documentation you removed perfectly match 
> the current code...
> 

strk,

First as we twiddle our thumbs more and more people are using PostGIS
2.0.0SVN in production mose
cause they have no choice -- they need the functionality and now you expect
them to 
do a dump / reload and for what? 

So they can get ~= to use an index which is not backward compatible even
with the same versions of PostGIS.
I took out of the the docs, because I don't want third party vendors relying
on it and scratching their head
when it behaves slower or different even on the same version of PostGIS.

I would also appreciate if you put && back for ST_Equals.  I need that I and
don't expect to have to do a dump
/ reload to get that to use an index.

You know what would be REALLY USEFUL.  IF we had a real geometric equality
operator like ~= used to be in 1.3
so that people who want to use CONSTRAINT EXCLUSION to enforce uniqueness of
their geometries CAN.


Regina