[Mapserver-users] GEOS: buffer function for MULTIPOLYGON geometry object

[songzh at cs.orst.edu]

Hello list:

  I recently tested GEOS 'buffer(MULTIPOLYGON_geo_column, 100)' function and
found something strange:
  1) I manually created a MULTIPOLYGON object which is shown as two trangles
connected by one point.
  2) then I issued command as: 
"update motelsites set buffer_py=buffer(the_geom_py,500) where gid=36;" 
  3) The strange thing is: only the left triangle has been buffered and the
buffer area has been shown around this triangle. The right triangle didn't show
up its buffered area at all.

  Did I do anything wrong or there is some problem with the GEOS's buffer
function to deal with MULTIPOLYGON object ?
  Thanks for any advice!


Zhigang Song