[postgis-users] Operator precision

Paul Ramsey pramsey at opengeo.org
Wed Feb 25 07:04:22 PST 2009


No, very large numbers do get indexed, they just don't get indexed
quite so precisely.

P.

On Wed, Feb 25, 2009 at 2:43 AM, Kemal Bayram <kemal at cins.co.uk> wrote:
> Thanks, that solved the problem but I'm guessing that very large numbers do
> not get indexed properly but then again if we're working with long/latitute
> ranges normally I guess it's not really a concern.
>
>> Add an "AND" clause that tests containment of the point
>> against a rectangular polygon. Or that does explict
>> ST_X(point) ST_Y(point) against your box. There's no way to
>> change the box2d behavior, and it's a feature, not a bug
>> (small boxes work better for large data sets, and spatial
>> index results are expected to be over-determined).
>>
>> P.
>>
>> On Mon, Feb 23, 2009 at 3:58 PM, Kemal Bayram
>> <kemal at cins.co.uk> wrote:
>> > Hello all,
>> >
>> > I'm a using PostGIS working with mainly points testing against 2d
>> > bounded boxes, I recently came across a problem that is
>> driving me nuts whereby:
>> >
>> > select makebox2d(makepoint(32.25, 34.9375),
>> makepoint(32.31249, 35))
>> > && makepoint(32.3125, 34.996448);
>> >
>> > returns false (as expected), where as:
>> >
>> >
>> > select makebox2d(makepoint(32.25, 34.9375),
>> makepoint(32.312499, 35))
>> > && makepoint(32.3125, 34.996448);
>> >
>> > returns true.
>> >
>> > 32.312499 cast as float4 is 32.3125, so I'm assuming that
>> internally
>> > single precision is being used. Is there any way change
>> this behaviour?
>> >
>> > Regards
>> > Kemal
>> > _______________________________________________
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>> >
>> >
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>
>
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