[postgis-users] error with buffer()

[Paul Ramsey]

Send in your geometry! Some geometry/parameter combinations break
ST_Buffer() and we like to add those to our zoo of unusual and
interesting cases for future improvement.

P

In the meantime, try slightly simplifying your geometry first, or
doing your buffer in 2 or more steps of smaller tolerances, or
sacrificing a goat before starting the function call... :)

On Tue, Apr 22, 2008 at 2:52 AM, Stefan Zweig <stefanzweig1881 at web.de> wrote:
>
>
>  hi list,
>
>  there seems to be an error within the buffer(geometry, precision) function.
>
>  i just tried to the following statement:
>  UPDATE _g2870 SET the_geom_3_b = buffer(the_geom_3, 0) WHERE isValid(the_geom_3) = false;
>  and it resulted into a broken connection to the postmaster. postgis seems to have problems with the buffer function and invalid geometries. the server.log says the following:
>
>  bufferOriginalPrecision failed (TopologyException: unable to assign hole to a shell), trying with reduced precision
>  recomputing with precision scale factor = 1e+12
>  Scaler: offsetX,Y: 0,0 scaleFactor: 1e+12
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 1e+12
>  recomputing with precision scale factor = 1e+11
>  Scaler: offsetX,Y: 0,0 scaleFactor: 1e+11
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 1e+11
>  recomputing with precision scale factor = 1e+10
>  Scaler: offsetX,Y: 0,0 scaleFactor: 1e+10
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 1e+10
>  recomputing with precision scale factor = 1e+09
>  Scaler: offsetX,Y: 0,0 scaleFactor: 1e+09
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 1e+09
>  recomputing with precision scale factor = 1e+08
>  Scaler: offsetX,Y: 0,0 scaleFactor: 1e+08
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 1e+08
>  recomputing with precision scale factor = 1e+07
>  Scaler: offsetX,Y: 0,0 scaleFactor: 1e+07
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 1e+07
>  recomputing with precision scale factor = 1e+06
>  Scaler: offsetX,Y: 0,0 scaleFactor: 1e+06
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 1e+06
>  recomputing with precision scale factor = 100000
>  Scaler: offsetX,Y: 0,0 scaleFactor: 100000
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 100000
>  recomputing with precision scale factor = 10000
>  Scaler: offsetX,Y: 0,0 scaleFactor: 10000
>  ReScaler: offsetX,Y: 0,0 scaleFactor: 10000
>  recomputing with precision scale factor = 1000
>  Scaler: offsetX,Y: 0,0 scaleFactor: 1000
>  pdata 10.100.6.140(1782) UPDATE: ../../source/headers/geos/noding/SegmentString.h:175: void geos::noding::SegmentString::testInvariant() const: Zusicherung »pts->size() > 1« nicht erfÌllt.
>  LOG: server process (PID 7510) was terminated by signal 6
>  LOG: terminating any other active server processes
>  WARNING: terminating connection because of crash of another server process
>  DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
>  HINT: In a moment you should be able to reconnect to the database and repeat your command.
>  WARNING: terminating connection because of crash of another server process
>  DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
>  HINT: In a moment you should be able to reconnect to the database and repeat your command.
>  LOG: all server processes terminated; reinitializing
>  LOG: database system was interrupted at 2008-04-22 11:18:52 CEST
>  LOG: checkpoint record is at 0/9A4F7BC8
>  LOG: redo record is at 0/9A4F7BC8; undo record is at 0/0; shutdown TRUE
>  LOG: next transaction ID: 0/51508; next OID: 322761
>  LOG: next MultiXactId: 1; next MultiXactOffset: 0
>  LOG: database system was not properly shut down; automatic recovery in progress
>  LOG: redo starts at 0/9A4F7C18
>  LOG: unexpected pageaddr 0/9161E000 in log file 0, segment 154, offset 6414336
>  LOG: redo done at 0/9A61D790
>  LOG: database system is ready
>
>
>  my postgis_version is:
>  select postgis_full_version()
>  "POSTGIS="1.3.3" GEOS="3.0.0-CAPI-1.4.1" PROJ="Rel. 4.6.0, 21 Dec 2007" USE_STATS"
>
>  any ideas?
>
>  regards,
>  stefan
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