[geos-devel] supporting filters

[Paul Ramsey]

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
>
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