[postgis-devel] EMPTY

[Paul Ramsey]

In the spirit of maintaining the geometry logical flow, what do you
think of these ideas?

 * ST_Contains(geometry, empty) == TRUE
 * ST_Within(geometry, empty) == FALSE
 * ST_Contains(empty, geometry) == FALSE
 * ST_Within(empty, geometry) == TRUE

What does SQL Server say?

P

On Tue, Oct 6, 2009 at 1:34 PM, Paul Ramsey <pramsey at cleverelephant.ca> wrote:
> I'm going to change my intersection/disjoint answers to agree w/ SQL
> Server. They are not bad, and they maintain the symmetry between where
> intersection => ! disjoint.
>
> P.
>
> On Tue, Oct 6, 2009 at 12:45 PM, Chris Hodgson <chodgson at refractions.net> wrote:
>> I moved these and summarized the interesting results from SQL Server 2008
>> next to your original lines Paul.
>>
>> Note that SQL Server says that everything is disjoint from empty, including
>> empty itself - whereas your original guesses were to return false.
>>
>> So far I think I like SQL Server's answers. Would be good to compare with
>> oracle spatial too.
>>
>> Chris
>>
>> Paul Ramsey wrote:
>>>
>>> Regina, could you move your SQL Server examples down to a big block at
>>> the end, so the main part of the document is more readable? So far I
>>> agree with SQL Server in all the examples! Those guys are smart! :)
>>>
>>> P
>>>
>>> On Tue, Oct 6, 2009 at 12:12 PM, Paul Ramsey <pramsey at cleverelephant.ca>
>>> wrote:
>>>
>>>>
>>>> On Tue, Oct 6, 2009 at 12:03 PM, Chris Hodgson <chodgson at refractions.net>
>>>> wrote:
>>>>
>>>>
>>>>>
>>>>> I would dare say that geometry empty is more like zero, than null.
>>>>>
>>>>
>>>> Bingo, there's a useful mental model. Wikify that!
>>>>
>>>>
>>>
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>>
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>