[geos-devel] supporting filters

[Paul Ramsey]

Oracle's understanding is the same as mine:

<http://download-west.oracle.com/docs/cd/B19306_01/appdev.102/b14255/ 
sdo_operat.htm#i77653>
On 28-May-07, at 7:41 PM, Paul Ramsey wrote:

> Is this the Oracle defn also? I had always interpreted DWithin to  
> mean "within distance of", so that
>
> DWIthin(A,B,100) was functionally equivalent to Distance(A,B) < 100
>
> P
>
> On 27-May-07, at 2:23 PM, Kralidis,Tom [Burlington] wrote:
>
>>
>> Further info from Peter Vretanos (FES 1.0.0 spec editor):
>>
>> "According to the BNF in the Cat 1.0 specification DWithin tests  
>> to see
>> whether geometry A is completely within a certain distance of  
>> geometry
>> B.
>>
>> I interpret this to mean a "buffer" query.  That is you create a  
>> buffer
>> around A at the specified distance and then do a WITHIN (as  
>> defined in
>> SFSQL) between this new buffer-expanded geometry (A') and the test
>> geometry B.  If B is completely within A' then the operator  
>> evaluates to
>> true
>>
>> BEYOND is the opposite of DWITHIN.   If B is completely outside of A'
>> then the operator evaluates to true."
>>
>> Cheers
>>
>> ..Tom
>>
>> _______________________________________________
>> geos-devel mailing list
>> geos-devel at geos.refractions.net
>> http://geos.refractions.net/mailman/listinfo/geos-devel
>
> _______________________________________________
> geos-devel mailing list
> geos-devel at geos.refractions.net
> http://geos.refractions.net/mailman/listinfo/geos-devel