[postgis-devel] EMPTY

[Paul Ramsey]

Meaning FFFFFFFFF ? :)

On Tue, Oct 6, 2009 at 2:25 PM, Martin Davis <mbdavis at refractions.net> wrote:
> FALSE!!!!
>
> Paul Ramsey wrote:
>>
>> OK, the uber question (Kevin can meditate over this one tonight):
>>
>> ST_Relate(geometry, empty)
>> ST_Relate(empty, empty)
>>
>>  :)
>>
>> On Tue, Oct 6, 2009 at 2:11 PM, Paragon Corporation <lr at pcorp.us> wrote:
>>
>>>
>>> Yap 0 on all counts.  Wow those Microsoft people are really smart.
>>>
>>>  --geometry contains empty
>>>  SELECT Geometry::STGeomFromText('POINT(1
>>> 2)',4326).STContains(Geometry::STGeomFromText('POLYGON EMPTY',4326))
>>>       => 0
>>>
>>> --geometry within empty
>>>  SELECT Geometry::STGeomFromText('POINT(1
>>> 2)',4326).STWithin(Geometry::STGeomFromText('POLYGON EMPTY',4326))
>>>        => 0
>>>
>>> --empty contains geometry
>>>  SELECT Geometry::STGeomFromText('POLYGON
>>> EMPTY',4326).STContains(Geometry::STGeomFromText('POINT(1 2)',4326))
>>>  => 0
>>>
>>>  --empty within geometry
>>> SELECT Geometry::STGeomFromText('POLYGON
>>> EMPTY',4326).STWithin(Geometry::STGeomFromText('POINT(1 2)',4326))
>>>  => 0
>>>
>>> Thanks,
>>> Regina
>>>
>>> -----Original Message-----
>>> From: postgis-devel-bounces at postgis.refractions.net
>>> [mailto:postgis-devel-bounces at postgis.refractions.net] On Behalf Of Chris
>>> Hodgson
>>> Sent: Tuesday, October 06, 2009 5:03 PM
>>> To: PostGIS Development Discussion
>>> Subject: Re: [postgis-devel] EMPTY
>>>
>>> I agree with you Regina, and I bet SQL Server does too.
>>>
>>> Chris
>>>
>>> Paragon Corporation wrote:
>>>
>>>>
>>>> They should all be false.
>>>>
>>>> Isn't the first requirement of containment/contains be that the two
>>>> geometries intersect -- so if we say empty can't intersect with
>>>> anything including empty, how can anything possibly contain  it?
>>>>
>>>> Though have to pull out my sql server 2008 to see if it is in agreement.
>>>>
>>>> Thanks,
>>>> Regina
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: postgis-devel-bounces at postgis.refractions.net
>>>> [mailto:postgis-devel-bounces at postgis.refractions.net] On Behalf Of
>>>> Paul Ramsey
>>>> Sent: Tuesday, October 06, 2009 4:39 PM
>>>> To: PostGIS Development Discussion
>>>> Subject: Re: [postgis-devel] EMPTY
>>>>
>>>> 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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>>>>>>
>>>>>>
>>>>
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>
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> Martin Davis
> Senior Technical Architect
> Refractions Research, Inc.
> (250) 383-3022
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