[postgis-users] how to polygonize a not closed linestring?

[Stefan Zweig]

hi list,

i have a problem with this query:
select buffer(simplify(the_geom,5.200001E-4),0) from table where gid=id;

i get this error message:

NOTICE:  IllegalArgumentException: points must form a closed linestring
ERROR: POSTGIS2GEOS conversion failed

i have just examined the geometry with giving it back using astext(the_geom). i have noticed, that in fact the first and the last point are not quite the same. but actually the last point of this geometry is near to the first, so it could be considered as the point before the last point. the only thing i would need now is a convenient way to "polygonize" my MULTIPOLYGON. i have noticed that in postgis there is a function st_polygonize but it is only applicable for a geometry set, not for a geometry. is there maybe another way to insert the first point again after the last point?

my geometry (i have shorten it) looks like this:

MULTIPOLYGON(((9.923602 50.695834,9.921405 50.695464,9.92042 50.697341,9.920536 50.697442,9.920996 50.69764,9.922744 50.695133,9.923889 50.695383)))


i appreciate any help, thanks in advance,

stefan
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