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

[Marc Jansen]

Hi Birgit,

you need an osgeo userid:

http://www.osgeo.org/osgeo_userid

Regards,
Marc


Birgit Laggner wrote:
> 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
>>>>
>>>>       
>>>>         
>>> _______________________________________________
>>> postgis-users mailing list
>>> postgis-users at postgis.refractions.net
>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>
>>>   
>>>       
>>     
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>
>   


-- 


  Dipl.-Geogr. Marc Jansen
  - Anwendungsentwickler -

  terrestris GmbH & Co. KG
  Irmintrudisstraße 17
  53111 Bonn

  Tel:    ++49 (0)228 / 96 28 99 -53
  Fax:    ++49 (0)228 / 96 28 99 -57

  Email:  jansen at terrestris.de
  Web:    http://www.terrestris.de

  Amtsgericht Bonn, HRA 6835
  Komplementärin:  terrestris Verwaltungsgesellschaft mbH
  vertreten durch: Hinrich Paulsen, Till Adams