[postgis-users] ST_RemoveRepeatedPoints failing to work?

[Lee Goddard]

Please forgive what may be a silly question, I am new to PostGIS.

I have the following:

     SELECT ST_AsKML(
         ST_RemoveRepeatedPoints(
             ST_Union(wkb_geometry)
         ), 0
     )

The beginning of the returned value looks like this:

<MultiGeometry><Polygon><outerBoundaryIs><LinearRing><coordinates>-156,20 -156,20 
-156,20 -156,20 -156,20 -156,20 -156,20 -156,20 -156,20 ...

The repeated points occur several hundred times.

The docs [1] say it can be safely called with any kind of geometry.

Does anyone know what I might be doing wrong? Or of another way to 
approach the problem of producing a smaller KML file (I compress to KMZ 
later) with perhaps less detail?

My version info is below [2].

Thanks in anticipation
Lee

[1] http://postgis.org/docs/ST_RemoveRepeatedPoints.html 
<http://postgis.org/docs/ST_RemoveRepeatedPoints.html>
[2]

SELECT PostGIS_full_version();
postgis_full_version
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  POSTGIS="2.1.1 r12113" GEOS="3.4.2-CAPI-1.8.2 r3921" PROJ="Rel. 4.8.0, 
6 March 2012" GDAL="GDAL 1.10.1, released 2013/08/26" LIBXML="2.7.3" 
LIBJSON="UNKNOWN" TOPOLOGY RASTER
(1 row)