[postgis-devel] EMPTY

[Paragon Corporation]

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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