[postgis-users] geos result sets

[Paul Ramsey]

Preferably a picture of the polygon AV says is "in" and we do not.

On Tuesday, February 24, 2004, at 08:56 AM, Paul Ramsey wrote:

> Can you give us a picture of your scenario? Asserting that ArcView is 
> "right" does not aid the debugging process. Probably the issue is one 
> of semantics around the OpenGIS predicates (we really need to write up 
> a page of description with pictures ... )
> P.
>
> On Tuesday, February 24, 2004, at 08:20 AM, James S reid wrote:
>
>> not disjoint() is worse!! in case its my sql heres the query :
>>
>> test=# select nuts3.* into temp from nuts2,nuts3 where not
>> disjoint(nuts3.the_geom,nuts2.the_geom) = TRUE and nuts2=2;
>>
>> essentially Ive two tables and im tryinbg to sd a polygon in polygon
>> selection - arcview correctly brings back 8 records - the above 
>> brings 15!!
>>
>> my original with within() qurey looked like:
>>
>> test=# select nuts3.* into temp from nuts2,nuts3 where
>> within(nuts3.the_geom,nuts2.the_geom) = TRUE and nuts2=2;
>>
>> this brought 7 polys back - 1 less than AV and I cant figire out my it
>> dislikes it !! BTW - reversing the tables and using a contains() also 
>> brings
>> back 7 polys so I think its something in the geos computation??
>>
>> however - my SQL may be naive so if anyone can correct me Id 
>> appreciate it
>> :)
>>
>> regards
>>
>> james
>>
>> ----- Original Message -----
>> From: "Paul Ramsey" <pramsey at refractions.net>
>> To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
>> Sent: Tuesday, February 24, 2004 3:50 PM
>> Subject: Re: [postgis-users] geos result sets
>>
>>
>>> The definition of Within() is not what you think it is.
>>> Try using "Not Disjoint()".
>>> P.
>>>
>>> On Tuesday, February 24, 2004, at 06:59 AM, James S reid wrote:
>>>
>>>> further to my eralier queries, Ive been doing some experimenting - i
>>>> consistently get less polys that Im convinced i should using the
>>>> within() operator on 2 tables (mr ESRI agrees with me) - so either 
>>>> the
>>>> geos computation is wrong, arcview is wrong or theres some subtlety 
>>>> in
>>>> the precision that im missing.
>>>>
>>>> has anyone else noticed weird things going on?
>>>>
>>>> Postgis 0.8.0/1 pg 7.4.1 geos 1.0 cywin environment
>>>>
>>>>
>>>> regards
>>>>
>>>> james
>>>> Edinburgh
>>>> _______________________________________________
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>>>>
>>>       Paul Ramsey
>>>       Refractions Research
>>>       Email: pramsey at refractions.net
>>>       Phone: (250) 885-0632
>>>
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>>
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>      Paul Ramsey
>      Refractions Research
>      Email: pramsey at refractions.net
>      Phone: (250) 885-0632
>
> _______________________________________________
> postgis-users mailing list
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>
      Paul Ramsey
      Refractions Research
      Email: pramsey at refractions.net
      Phone: (250) 885-0632