[postgis-users] ST_Centroid error on very small polygon

2012-06-22 Thread Sandor Csaba 
Hi List,

I cannot find answer to this phenomenon:

When I do this select on a very small polygon made of 3 points I get
an empty collection:

VT=# select ST_AsText(ST_Centroid(ST_GeomFromText('POLYGON((56.528667
25.210167,56.529 25.2105,56.528833 25.210333,56.528667
25.210167))')));
    st_astext
--
 GEOMETRYCOLLECTION EMPTY
(1 row)

If I modify one value just a little bit (56.529=56.5291) I
get correct results:

VT=# select ST_AsText(ST_Centroid(ST_GeomFromText('POLYGON((56.528667
25.210167,56.5291 25.2105,56.528833
25.210333,56.528667 25.210167))')));
    st_astext
--
 POINT(56.52887 25.21033)
(1 row)


Any of you seen such thing?

Thank you very much for your help!

Csaba


Versions:


 POSTGIS=1.5.2 GEOS=3.2.2-CAPI-1.6.2 PROJ=Rel. 4.7.1, 23
September 2009 LIBXML=2.7.6 USE_STATS


 PostgreSQL 8.4.11 on x86_64-pc-linux-gnu, compiled by GCC
gcc-4.4.real (Ubuntu 4.4.3-4ubuntu5) 4.4.3, 64-bit

--
Sándor Csaba
szolgáltatási vezető
ViaMap Kft.
Székhely/postacím: 2176 Erdőkürt, Téglaház utca 4.

Iroda:
1076 Budapest, Garay u. 29-31. I. 1.
(EMLA Környezeti Management és Jog Egyesület)


Tel: +3630/9605853
Fax: +3617002542
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Re: [postgis-users] ST_Centroid error on very small polygon

2012-06-22 Thread Sandro Santilli 
On Fri, Jun 22, 2012 at 11:39:52AM +0200, Sandor Csaba wrote:

 VT=# select ST_AsText(ST_Centroid(ST_GeomFromText('POLYGON((56.528667
 25.210167,56.529 25.2105,56.528833 25.210333,56.528667
 25.210167))')));
     st_astext
 --
  GEOMETRYCOLLECTION EMPTY
 (1 row)
...
 Any of you seen such thing?

I can reproduce this. The polygon is valid.
Definitely a bug. Could you file a ticket please ?

--strk;

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 http://www.gnu.org/philosophy/free-sw.html
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Re: [postgis-users] ST_Centroid error on very small polygon

2012-06-22 Thread Sandor Csaba 
Sorry for mixing threads up in the conversation.

I will try to file the ticket

Csaba

On 22 June 2012 12:30, Sandro Santilli s...@keybit.net wrote:
 On Fri, Jun 22, 2012 at 11:39:52AM +0200, Sandor Csaba wrote:

 VT=# select ST_AsText(ST_Centroid(ST_GeomFromText('POLYGON((56.528667
 25.210167,56.529 25.2105,56.528833 25.210333,56.528667
 25.210167))')));
     st_astext
 --
  GEOMETRYCOLLECTION EMPTY
 (1 row)
 ...
 Any of you seen such thing?

 I can reproduce this. The polygon is valid.
 Definitely a bug. Could you file a ticket please ?

 --strk;

  Sent from our free software
  http://www.gnu.org/philosophy/free-sw.html
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 postgis-users@postgis.refractions.net
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-- 
Sándor Csaba
szolgáltatási vezető
ViaMap Kft.
Székhely/postacím: 2176 Erdőkürt, Téglaház utca 4.

Iroda:
1076 Budapest, Garay u. 29-31. I. 1.
(EMLA Környezeti Management és Jog Egyesület)


Tel: +3630/9605853
Fax: +3617002542
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