[postgis-users] extent changed a little in rc3

[strk at refractions.net]

Bernhard,Mark
I can take the box2d output back to .15g, but be aware that box2d
uses single precision, not double, so the 1.0000001 would become
1.00000011920929, and not 1.0000001 as you would expect.

.8g would give it as written (for this specific case ;)).
The python site you mentioned suggests 17, but I think they
are referring to double precision, not single.

Currently the default is used, which is 6.

Give your numbers ;)

--strk;

On Tue, Mar 15, 2005 at 10:20:59AM -0000, Mark Cave-Ayland wrote:
> Hi strk/Bernhard,
> 
> > -----Original Message-----
> > From: postgis-users-bounces at postgis.refractions.net 
> > [mailto:postgis-users-bounces at postgis.refractions.net] On 
> > Behalf Of strk at refractions.net
> > Sent: 14 March 2005 21:14
> > To: postgis-users at postgis.refractions.net
> > Subject: Re: [postgis-users] extent changed a little in rc3
> 
> (cut)
> 
> > > So, the upshot this is: I think it's better to report reasonably 
> > > accurate values in the textual representations of postgis 
> > types than 
> > > trying to hide the effects of binary floating point.
> > 
> > You're probably right, it was a bad idea changing it...
> > Anyone else's opinion on this ?
> 
> I think that reporting the accurate value is the way to go, as suggested by
> the poster. My suspicion is that most people using PostGIS would already be
> aware of the effect of floating point rounding errors, but I think I would
> be surprised if my highly accurate data was displayed differently from its
> actual value in the DB.... I would consider rounding to be something done at
> the application layer if required.
> 
> 
> Kind regards,
> 
> Mark.
> 
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