[postgis-users] st_area and 0.001953125 (Possible Bug)

[Birgit Laggner]

Hi Marc,

I only wanted to remark that not only small polygons are affected by
this phenomenon - all areas I calculated with st_area() are multiples of
0.001953125 (what's not as it should be as appears to me).

I would have commented this at the link you attached, but I don't know
how (do I have to login or anything else?).

Regards,

Birgit.


On 15.04.2010 15:51, Marc Jansen wrote:
> Hi Birgit,
>
> good catch. I am pretty sure this is some sort of a bug, possibly
> related to 32-/64-bit architecture.
>
> I opened a bug [1], and cced Birgit. Add comments there as you dig
> deeper.
>
> Regards,
> Marc
>
> [1] http://trac.osgeo.org/postgis/ticket/503
>
>
> Birgit Laggner wrote:
>> Hi Maxime,
>>
>> well, this would argue against the guess from Marc regarding the
>> versions change from 1.4.0 to 1.4.1 (I can't imagine that 1.5.1 has
>> errors that were already debugged in 1.4.1). What catches my eye is that
>> all systems that show the error are 64-bit systems and the one from Marc
>> providing the true result is a 32-bit system. Maybe this could be
>> leading to an explanation??
>>
>> Thanks  and regards,
>>
>> Birgit.
>>
>>
>> On 15.04.2010 13:48, Maxime van Noppen wrote:
>>  
>>> On 04/15/2010 01:37 PM, Marc Jansen wrote:
>>>      
>>>> Hi Birgit,
>>>>
>>>> I can confirm your results on
>>>>           
>>> To help tracking down the bug: I have the same problem (areas
>>> 0.001953125 or 0 for the query on the pastebin) on :
>>>
>>> PostgreSQL 8.4.3 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC)
>>> 4.4.3 20100316 (prerelease), 64-bit
>>>
>>> POSTGIS="1.5.1" GEOS="3.2.0-CAPI-1.6.0" PROJ="Rel. 4.7.1, 23 September
>>> 2009" LIBXML="2.7.6" USE_STATS
>>>
>>>       
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>>   
>
>