diff --git a/.gitignore b/.gitignore
index 6789011420f..0500abd1597 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,8 +2,9 @@
 *.la
 .libs
 *.lo
+*~
 gmon.out
-install-sh
+/install-sh
 postgis_svn_revision.h
 aclocal.m4
 autom4te.cache/
@@ -86,6 +87,7 @@ postgis/legacy_gist.sql
 postgis/legacy_minimal.sql
 postgis/legacy.sql
 postgis/postgis.sql
+postgis/pipeline_gis.sql
 postgis/postgis_upgrade.sql*
 postgis/sfcgal_upgrade.sql*
 postgis/sqldefines.h
@@ -128,11 +130,8 @@ topology/test/load_topology.sql
 topology/test/topo_predicates.sql
 topology/test/regress/topogeo_addlinestring_expected
 topology/topology_drop_after.sql
-topology/topology_drop_after.sql.in
 topology/topology_drop_before.sql
-topology/topology_drop_before.sql.in
 topology/topology.sql
-topology/topology.sql.in
 topology/topology_upgrade.sql*
 topology/uninstall_topology.sql
 libpgcommon/Makefile
diff --git a/GNUmakefile.in b/GNUmakefile.in
index a7492c06d67..a04ecec3db3 100644
--- a/GNUmakefile.in
+++ b/GNUmakefile.in
@@ -5,7 +5,7 @@
 #-----------------------------------------------------
 
 # todo: add all subdirs
-SUBDIRS = liblwgeom libpgcommon postgis regress @RASTER@ @TOPOLOGY@ loader utils doc @EXTENSIONS@
+SUBDIRS = liblwgeom libpgcommon postgis regress @RASTER@ @TOPOLOGY@ loader utils @EXTENSIONS@
 
 PERL = @PERL@
 
@@ -21,11 +21,11 @@ all install uninstall noop clean distclean check:
 
 all: postgis_svn_revision.h
 
-install: all comments-install
+install: all # comments-install
 
 uninstall: docs-uninstall comments-uninstall
 
-clean: docs-clean clean-local
+clean: clean-local
 
 clean-local:
 	rm -f postgis.sql postgis_upgrade.sql
diff --git a/configure.ac b/configure.ac
index e3e7c376661..d67532a8cc2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,6 +3,7 @@ dnl *
 dnl * PostGIS - Spatial Types for PostgreSQL
 dnl * http://postgis.net
 dnl * Copyright 2008 Mark Cave-Ayland
+dnl * Portions Copyright 2013-2015 PipelineDB
 dnl *
 dnl * This is free software; you can redistribute and/or modify it under
 dnl * the terms of the GNU General Public Licence. See the COPYING file.
@@ -162,7 +163,7 @@ dnl
 dnl Search for xsltproc which is required for building documentation
 dnl
 
-CAN_BUILD_COMMENTS=yes
+CAN_BUILD_COMMENTS=no
 
 AC_PATH_PROG([XSLTPROC], [xsltproc], [])
 if test "x$XSLTPROC" = "x"; then
@@ -373,16 +374,16 @@ if test "x$PG_CONFIG" = "xno"; then
 
 elif test "x$PG_CONFIG" = "x"; then
 	dnl PG_CONFIG was not specified, so search within the current path
-	AC_PATH_PROG([PG_CONFIG], [pg_config])
+	AC_PATH_PROG([PG_CONFIG], [pipeline-config])
 
 	dnl If we couldn't find pg_config, display an error
 	if test "x$PG_CONFIG" = "x"; then
-		AC_MSG_ERROR([could not find pg_config within the current path. You may need to try re-running configure with a --with-pg_config parameter.])
+		AC_MSG_ERROR([could not find pipeline-config within the current path. You may need to try re-running configure with a --with-pg_config parameter.])
 	fi
 else
 	dnl PG_CONFIG was specified; display a message to the user
 	if test "x$PG_CONFIG" = "xyes"; then
-		AC_MSG_ERROR([you must specify a parameter to --with-pgconfig, e.g. --with-pgconfig=/path/to/pg_config])
+		AC_MSG_ERROR([you must specify a parameter to --with-pgconfig, e.g. --with-pgconfig=/path/to/pipeline-config])
 	else
 		if test -f $PG_CONFIG; then
 			AC_MSG_RESULT([Using user-specified pg_config file: $PG_CONFIG])
@@ -1283,9 +1284,6 @@ AC_OUTPUT([GNUmakefile
    topology/Makefile 
    topology/test/Makefile 
    regress/Makefile 
-   doc/Makefile 
-   doc/Makefile.comments 
-   doc/html/image_src/Makefile 
    utils/Makefile 
    java/jdbc/Makefile
    $RT_MAKEFILE_LIST])
diff --git a/extensions/address_standardizer/.gitignore b/extensions/address_standardizer/.gitignore
new file mode 100644
index 00000000000..d50b8146c1f
--- /dev/null
+++ b/extensions/address_standardizer/.gitignore
@@ -0,0 +1 @@
+/sql
diff --git a/extensions/postgis/Makefile.in b/extensions/postgis/Makefile.in
index 088c1466633..cf89b2bbf4e 100644
--- a/extensions/postgis/Makefile.in
+++ b/extensions/postgis/Makefile.in
@@ -37,7 +37,7 @@ ifeq ($(PG91),yes)
 	
 all: sql/$(EXTENSION)--$(EXTVERSION).sql sql/$(EXTENSION)--unpackaged--$(EXTVERSION).sql sql/$(EXTENSION)--$(EXTVERSION)--$(EXTVERSION)next.sql sql/$(EXTENSION)--$(EXTVERSION)next--$(EXTVERSION).sql sql_minor_upgrade
 
-sql/$(EXTENSION).sql: sql_bits/postgis.sql sql_bits/postgis_comments.sql sql_bits/rtpostgis.sql sql_bits/mark_editable_objects.sql.in sql_bits/raster_comments.sql sql_bits/spatial_ref_sys.sql
+sql/$(EXTENSION).sql: sql_bits/postgis.sql sql_bits/postgis_comments.sql sql_bits/rtpostgis.sql sql_bits/mark_editable_objects.sql.in sql_bits/raster_comments.sql sql_bits/spatial_ref_sys.sql sql_bits/pipeline_gis.sql
 	mkdir -p sql
 	echo '\echo Use "CREATE EXTENSION $(EXTENSION)" to load this file. \quit' > $@
 	cat $^ >> $@
@@ -46,9 +46,9 @@ sql/$(EXTENSION)--$(EXTVERSION).sql: sql/$(EXTENSION).sql
 	mkdir -p sql
 	cp $< $@
 
-sql/$(EXTENSION)--unpackaged--$(EXTVERSION).sql: ../../postgis/postgis.sql ../../raster/rt_pg/rtpostgis.sql ../../utils/create_unpackaged.pl
+sql/$(EXTENSION)--unpackaged--$(EXTVERSION).sql: ../../postgis/postgis.sql ../../raster/rt_pg/rtpostgis.sql ../../utils/create_unpackaged.pl ../../postgis/pipeline_gis.sql
 	mkdir -p sql
-	cat ../../postgis/postgis.sql ../../raster/rt_pg/rtpostgis.sql | $(PERL) ../../utils/create_unpackaged.pl postgis > $@
+	cat ../../postgis/postgis.sql ../../raster/rt_pg/rtpostgis.sql ../../postgis/pipeline_gis.sql | $(PERL) ../../utils/create_unpackaged.pl postgis > $@
 	
 #this is a cludge to allow upgrading from same SVN to same SVN
 sql/$(EXTENSION)--$(EXTVERSION)--$(EXTVERSION)next.sql: sql_bits/postgis_raster_upgrade_minor.sql
@@ -64,11 +64,14 @@ sql_bits/spatial_ref_sys.sql: ../../spatial_ref_sys.sql
 sql_bits/postgis.sql: ../../postgis/postgis.sql
 	sed -e 's/BEGIN;//g' -e 's/COMMIT;//g'  $< > $@
 
+sql_bits/pipeline_gis.sql: ../../postgis/pipeline_gis.sql
+	sed -e 's/BEGIN;//g' -e 's/COMMIT;//g'  $< > $@
+
 ../../doc/postgis_comments.sql:
 	$(MAKE) -C ../../doc comments
 
-sql_bits/postgis_comments.sql: ../../doc/postgis_comments.sql
-	cp $< $@
+sql_bits/postgis_comments.sql: 
+	touch $@
 
 #strip BEGIN/COMMIT since these are not allowed in extensions
 sql_bits/rtpostgis.sql: ../../raster/rt_pg/rtpostgis.sql
@@ -98,13 +101,13 @@ sql_bits/postgis_upgrade.sql: ../../postgis/postgis_upgrade.sql
 ../../doc/raster_comments.sql:
 	$(MAKE) -C ../../doc comments
 
-sql_bits/raster_comments.sql: ../../doc/raster_comments.sql
-	cp $< $@
+sql_bits/raster_comments.sql: 
+	touch $@
 
 #postgis_raster_upgrade_minor.sql is the one that contains both postgis AND raster
 #TODO: come up with a better name
 #TODO: what about postgis_drop_after.sql ? where does it fit ??
-sql_bits/postgis_raster_upgrade_minor.sql: ../postgis_extension_helper.sql sql_bits/postgis_upgrade.sql sql_bits/rtpostgis_upgrade.sql ../../doc/raster_comments.sql ../../doc/postgis_comments.sql ../postgis_extension_helper_uninstall.sql
+sql_bits/postgis_raster_upgrade_minor.sql: ../postgis_extension_helper.sql sql_bits/postgis_upgrade.sql sql_bits/rtpostgis_upgrade.sql sql_bits/raster_comments.sql sql_bits/postgis_comments.sql ../postgis_extension_helper_uninstall.sql
 	echo '\echo Use "CREATE EXTENSION $(EXTENSION)" to load this file. \quit' > $@
 	cat $^ >> $@
 
diff --git a/extensions/postgis_tiger_geocoder/Makefile.in b/extensions/postgis_tiger_geocoder/Makefile.in
index 4240c748960..f72ac15d30a 100644
--- a/extensions/postgis_tiger_geocoder/Makefile.in
+++ b/extensions/postgis_tiger_geocoder/Makefile.in
@@ -129,8 +129,8 @@ sql_bits/add_search_path.sql: sql_bits/add_search_path.sql.in
 ../../doc/tiger_geocoder_comments.sql:
 	$(MAKE) -C ../../doc comments
 	
-sql_bits/tiger_geocoder_comments.sql: ../../doc/tiger_geocoder_comments.sql
-	cp $< $@
+sql_bits/tiger_geocoder_comments.sql:
+	touch $@
 	
 #grep all lines that start with CREATE OR REPLACE FUNCTION, TRIGGER...
 #then replace CREATE OR REPLACE .. with ALTER EXTENSION..;
diff --git a/extensions/postgis_topology/Makefile.in b/extensions/postgis_topology/Makefile.in
index 832d2cc8eb0..4ddda3de0ff 100644
--- a/extensions/postgis_topology/Makefile.in
+++ b/extensions/postgis_topology/Makefile.in
@@ -55,8 +55,8 @@ sql_bits/topology.sql: ../../topology/topology.sql
 ../../doc/topology_comments.sql:
 	$(MAKE) -C ../../doc comments
 	
-sql_bits/topology_comments.sql: ../../doc/topology_comments.sql
-	cp $< $@
+sql_bits/topology_comments.sql: 
+	touch $@
 	
 sql/$(EXTENSION)--unpackaged--$(EXTVERSION).sql: ../../topology/topology.sql ../../utils/create_unpackaged.pl
 	mkdir -p sql
diff --git a/liblwgeom/Makefile.in b/liblwgeom/Makefile.in
index 1c4d08e5abc..1dd790a7f03 100644
--- a/liblwgeom/Makefile.in
+++ b/liblwgeom/Makefile.in
@@ -3,6 +3,7 @@
 # * PostGIS - Spatial Types for PostgreSQL
 # * http://postgis.net
 # * Copyright 2008 Mark Cave-Ayland
+# * Portions Copyright 2013-2015 PipelineDB
 # *
 # * This is free software; you can redistribute and/or modify it under
 # * the terms of the GNU General Public Licence. See the COPYING file.
@@ -24,6 +25,9 @@ LIBTOOL = @LIBTOOL@
 
 SOVER = @POSTGIS_MAJOR_VERSION@.@POSTGIS_MINOR_VERSION@.@POSTGIS_MICRO_VERSION@
 
+PG_CONFIG = @PG_CONFIG@
+LIB_INSTALL_PATH = $(shell $(PG_CONFIG) --libdir)
+LIB_INCLUDE_PATH = $(shell $(PG_CONFIG) --includedir)
 
 YACC=@YACC@
 LEX=@LEX@
@@ -120,8 +124,8 @@ install: install-liblwgeom
 uninstall: uninstall-liblwgeom
 
 install-liblwgeom: liblwgeom.la
-	$(LIBTOOL) --mode=install $(INSTALL) liblwgeom.la "$(DESTDIR)$(libdir)/liblwgeom.la"
-	$(INSTALL) liblwgeom.h "$(DESTDIR)$(includedir)/liblwgeom.h"
+	$(LIBTOOL) --mode=install $(INSTALL) liblwgeom.la "$(LIB_INSTALL_PATH)/liblwgeom.la"
+	$(INSTALL) -m 0644 liblwgeom.h "$(LIB_INCLUDE_PATH)/liblwgeom.h"
 
 uninstall-liblwgeom:
 	$(LIBTOOL) --mode=uninstall rm -f "$(DESTDIR)$(libdir)/liblwgeom.la"
diff --git a/postgis/Makefile.in b/postgis/Makefile.in
index af0a839901e..a6031599dcd 100644
--- a/postgis/Makefile.in
+++ b/postgis/Makefile.in
@@ -3,6 +3,7 @@
 # * PostGIS - Spatial Types for PostgreSQL
 # * http://postgis.net
 # * Copyright 2008 Mark Cave-Ayland
+# * Portions Copyright 2013-2015 PipelineDB
 # *
 # * This is free software; you can redistribute and/or modify it under
 # * the terms of the GNU General Public Licence. See the COPYING file.
@@ -14,11 +15,11 @@ MODULE_big=postgis-@POSTGIS_MAJOR_VERSION@.@POSTGIS_MINOR_VERSION@
 MODULEDIR=contrib/$(MODULE_big)
 
 # Files to be copied to the contrib/ directory
-SQL_built=postgis.sql uninstall_postgis.sql postgis_upgrade.sql  legacy.sql uninstall_legacy.sql legacy_minimal.sql legacy_gist.sql 
+SQL_built=postgis.sql uninstall_postgis.sql postgis_upgrade.sql  legacy.sql uninstall_legacy.sql legacy_minimal.sql legacy_gist.sql pipeline_gis.sql
 DATA=../spatial_ref_sys.sql
 
 # SQL objects (files requiring pre-processing)
-SQL_objs=postgis.sql legacy.sql legacy_minimal.sql
+SQL_objs=postgis.sql legacy.sql legacy_minimal.sql pipeline_gis.sql
 
 GEOM_BACKEND_OBJ = lwgeom_geos.o
 SFCGAL_BACKEND_OBJ = lwgeom_sfcgal.o
diff --git a/postgis/lwgeom_accum.c b/postgis/lwgeom_accum.c
index 1a09bbd21b1..c4cfb7fb11d 100644
--- a/postgis/lwgeom_accum.c
+++ b/postgis/lwgeom_accum.c
@@ -2,7 +2,8 @@
  *
  * PostGIS - Spatial Types for PostgreSQL
  * http://postgis.net
- * Copyright 2009 Paul Ramsey <pramsey@opengeo.org>
+ * Portions Copyright 2009 Paul Ramsey <pramsey@opengeo.org>
+ * Portions Copyright 2013-2015 PipelineDB
  *
  * This is free software; you can redistribute and/or modify it under
  * the terms of the GNU General Public Licence. See the COPYING file.
@@ -13,6 +14,8 @@
 #include "fmgr.h"
 #include "funcapi.h"
 #include "access/tupmacs.h"
+#include "lib/stringinfo.h"
+#include "libpq/pqformat.h"
 #include "utils/array.h"
 #include "utils/lsyscache.h"
 
@@ -87,6 +90,79 @@ pgis_abs_out(PG_FUNCTION_ARGS)
 	PG_RETURN_POINTER(NULL);
 }
 
+/*
+ * Serializes as pgis_abs
+ */
+PG_FUNCTION_INFO_V1(pgis_abs_send);
+Datum
+pgis_abs_send(PG_FUNCTION_ARGS)
+{
+	pgis_abs *p = (pgis_abs *) PG_GETARG_POINTER(0);
+	ArrayType *arr = DirectFunctionCall1(arrayaggstatesend, (Datum) p->a);
+
+	PG_RETURN_ARRAYTYPE_P(arr);
+}
+
+/*
+ * Deserializes a pgis_abs
+ */
+PG_FUNCTION_INFO_V1(pgis_abs_recv);
+Datum
+pgis_abs_recv(PG_FUNCTION_ARGS)
+{
+	MemoryContext context;
+	MemoryContext old;
+	pgis_abs *result;
+	ArrayType *arr;
+
+	if (!AggCheckCallContext(fcinfo, &context))
+		context = fcinfo->flinfo->fn_mcxt;
+
+	old = MemoryContextSwitchTo(context);
+
+	arr = (ArrayType *) PG_GETARG_ARRAYTYPE_P_COPY(0);
+	fcinfo->arg[0] = (Datum) arr;
+	result = palloc0(sizeof(pgis_abs));
+	result->a = (ArrayBuildState *) arrayaggstaterecv(fcinfo);
+
+	MemoryContextSwitchTo(old);
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+ * Combines two pgis_abs transition states into one
+ */
+PG_FUNCTION_INFO_V1(pgis_geometry_accum_combinefn);
+Datum
+pgis_geometry_accum_combinefn(PG_FUNCTION_ARGS)
+{
+	MemoryContext old;
+	MemoryContext aggcontext;
+	pgis_abs *state = PG_ARGISNULL(0) ? NULL : (pgis_abs *) PG_GETARG_POINTER(0);
+	pgis_abs *incoming = (pgis_abs *) PG_GETARG_POINTER(1);
+	int i;
+
+	if (!AggCheckCallContext(fcinfo, &aggcontext))
+		elog(ERROR, "pgis_geometry_accum_combinefn called in non-aggregate context");
+
+	if (state == NULL)
+		PG_RETURN_POINTER(incoming);
+
+	old = MemoryContextSwitchTo(aggcontext);
+
+	for (i=0; i<incoming->a->nelems; i++)
+	{
+		state->a = accumArrayResult(state->a,
+				incoming->a->dvalues[i], incoming->a->dnulls[i],
+				incoming->a->element_type, aggcontext);
+	}
+
+	MemoryContextSwitchTo(old);
+
+	PG_RETURN_POINTER(state);
+}
+
 /**
 ** The transfer function hooks into the PostgreSQL accumArrayResult()
 ** function (present since 8.0) to build an array in a side memory
diff --git a/postgis/lwgeom_box3d.c b/postgis/lwgeom_box3d.c
index 73fb7d02248..d87e3b54183 100644
--- a/postgis/lwgeom_box3d.c
+++ b/postgis/lwgeom_box3d.c
@@ -2,6 +2,8 @@
  *
  * BOX3D IO and conversions
  *
+ * Portions Copyright 2013-2015 PipelineDB
+ *
  **********************************************************************/
 
 #include "postgres.h"
@@ -340,6 +342,31 @@ Datum BOX3D_zmax(PG_FUNCTION_ARGS)
 	PG_RETURN_FLOAT8(Max(box->zmin, box->zmax));
 }
 
+PG_FUNCTION_INFO_V1(BOX3D_combine_3d);
+Datum BOX3D_combine_3d(PG_FUNCTION_ARGS)
+{
+	BOX3D *state;
+	BOX3D *incoming = (BOX3D *) PG_GETARG_POINTER(1);
+
+	if (PG_ARGISNULL(0))
+	{
+		if (PG_ARGISNULL(1))
+			PG_RETURN_NULL();
+		PG_RETURN_POINTER(incoming);
+	}
+
+	state = (BOX3D *) PG_GETARG_POINTER(0);
+
+	state->xmax = Max(state->xmax, incoming->xmax);
+	state->ymax = Max(state->ymax, incoming->ymax);
+	state->zmax = Max(state->zmax, incoming->zmax);
+	state->xmin = Min(state->xmin, incoming->xmin);
+	state->ymin = Min(state->ymin, incoming->ymin);
+	state->zmin = Min(state->zmin, incoming->zmin);
+
+	PG_RETURN_POINTER(state);
+}
+
 /**
 * Used in the ST_Extent and ST_Extent3D aggregates, does not read the 
 * serialized cached bounding box (since that is floating point)
diff --git a/postgis/pipeline_gis.sql.in b/postgis/pipeline_gis.sql.in
new file mode 100644
index 00000000000..0a2395ef1a7
--- /dev/null
+++ b/postgis/pipeline_gis.sql.in
@@ -0,0 +1,241 @@
+-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+--
+--
+-- PostGIS - Support for PipelineDB
+-- http://postgis.net
+-- Copyright 2013-2015 PipelineDB
+--
+-- This is free software; you can redistribute and/or modify it under
+-- the terms of the GNU General Public Licence v3.
+--
+-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+-------------------------------------------------------------------------------
+-- ST_SummaryStatsAgg combiner
+-------------------------------------------------------------------------------
+
+CREATE FUNCTION summarystatssend(internal)
+	RETURNS bytea
+	AS '$libdir/rtpostgis-2.2'
+	LANGUAGE c;
+
+CREATE FUNCTION summarystatsrecv(bytea)
+	RETURNS bytea
+	AS '$libdir/rtpostgis-2.2'
+	LANGUAGE c;
+
+CREATE FUNCTION _st_summarystats_combinefn(internal, internal)
+  RETURNS internal
+	AS '$libdir/rtpostgis-2.2', 'RASTER_summaryStats_combinefn'
+  LANGUAGE c;
+
+-- The transition functions for each transition function's signature all have the same name,
+-- so we need to select each one individually in order to properly construct pipeline_combine entries
+INSERT INTO pipeline_combine VALUES (
+'_st_summarystats_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_summarystats_transfn' AND pronargs = 5),
+'summarystatssend', 'summarystatsrecv', '_st_summarystats_combinefn', 17);
+
+INSERT INTO pipeline_combine VALUES (
+'_st_summarystats_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_summarystats_transfn' AND pronargs = 4 AND proargtypes[3] = 16),
+'summarystatssend', 'summarystatsrecv', '_st_summarystats_combinefn', 17);
+
+INSERT INTO pipeline_combine VALUES (
+'_st_summarystats_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_summarystats_transfn' AND pronargs = 4 AND proargtypes[3] = 701),
+'summarystatssend', 'summarystatsrecv', '_st_summarystats_combinefn', 17);
+
+-------------------------------------------------------------------------------
+-- ST_Union(raster) combiner
+-------------------------------------------------------------------------------
+
+CREATE FUNCTION unionargsend(internal)
+	RETURNS bytea
+	AS '$libdir/rtpostgis-2.2'
+	LANGUAGE c;
+
+CREATE FUNCTION unionargrecv(bytea)
+	RETURNS bytea
+	AS '$libdir/rtpostgis-2.2'
+	LANGUAGE c;
+
+CREATE FUNCTION _st_union_combinefn(internal)
+	RETURNS internal
+	AS '$libdir/rtpostgis-2.2', 'RASTER_union_combinefn'
+  LANGUAGE c;
+
+-- The transition functions for each transition function's signature all have the same name,
+-- so we need to select each one individually in order to properly construct pipeline_combine entries
+INSERT INTO pipeline_combine VALUES (
+'_st_union_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_union_transfn' AND pronargs = 2),
+'unionargsend', 'unionargrecv', '_st_union_combinefn', 17);
+
+INSERT INTO pipeline_combine VALUES (
+'_st_union_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_union_transfn' AND pronargs = 4),
+'unionargsend', 'unionargrecv', '_st_union_combinefn', 17);
+
+INSERT INTO pipeline_combine VALUES (
+'_st_union_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_union_transfn' AND pronargs = 3 AND proargtypes[2] = 23),
+'unionargsend', 'unionargrecv', '_st_union_combinefn', 17);
+
+INSERT INTO pipeline_combine VALUES (
+'_st_union_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_union_transfn' AND pronargs = 3 AND proargtypes[2] = 25),
+'unionargsend', 'unionargrecv', '_st_union_combinefn', 17);
+
+INSERT INTO pipeline_combine VALUES (
+'_st_union_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_union_transfn' AND pronargs = 3 AND proargtypes[2] NOT IN (23, 25)),
+'unionargsend', 'unionargrecv', '_st_union_combinefn', 17);
+
+-------------------------------------------------------------------------------
+-- ST_Extent combiner
+-------------------------------------------------------------------------------
+
+CREATE FUNCTION combine_box3d(internal)
+	RETURNS box3d
+	AS 'MODULE_PATHNAME', 'BOX3D_combine_3d'
+	LANGUAGE c;
+
+INSERT INTO pipeline_combine VALUES (
+(SELECT oid FROM pg_proc WHERE proname = 'box2d' AND proargtypes[0] =
+	(SELECT oid FROM pg_type WHERE typname = 'box3d')),
+(SELECT oid FROM pg_proc WHERE proname = 'st_combine_bbox' AND prorettype =
+	(SELECT oid FROM pg_type WHERE typname = 'box3d')),
+0, 0, 'combine_box3d',
+(SELECT oid FROM pg_type WHERE typname = 'box3d'));
+
+-------------------------------------------------------------------------------
+-- ST_3DExtent combiner
+-------------------------------------------------------------------------------
+
+INSERT INTO pipeline_combine VALUES (0,
+(SELECT oid FROM pg_proc WHERE proname = 'st_combine_bbox' AND prorettype =
+	(SELECT oid FROM pg_type WHERE typname = 'box3d')),
+0, 0, 'combine_box3d',
+(SELECT oid FROM pg_type WHERE typname = 'box3d'));
+
+-------------------------------------------------------------------------------
+-- ST_Accum combiner
+-------------------------------------------------------------------------------
+
+CREATE FUNCTION pgis_geometry_accum_combinefn(pgis_abs, pgis_abs)
+  RETURNS pgis_abs
+	AS 'MODULE_PATHNAME'
+  LANGUAGE c;
+
+CREATE FUNCTION pgis_abs_send(anyelement)
+  RETURNS anyarray
+	AS 'MODULE_PATHNAME'
+  LANGUAGE c;
+
+CREATE FUNCTION pgis_abs_recv(anyarray)
+  RETURNS pgis_abs
+	AS 'MODULE_PATHNAME'
+  LANGUAGE c;
+
+INSERT INTO pipeline_combine VALUES (
+'pgis_geometry_accum_finalfn',
+'pgis_geometry_accum_transfn',
+'pgis_abs_send', 'pgis_abs_recv', 'pgis_geometry_accum_combinefn', 2277);
+
+-------------------------------------------------------------------------------
+-- ST_Union(geometry) combiner
+-------------------------------------------------------------------------------
+
+INSERT INTO pipeline_combine VALUES (
+'pgis_geometry_union_finalfn',
+'pgis_geometry_accum_transfn',
+'pgis_abs_send', 'pgis_abs_recv', 'pgis_geometry_accum_combinefn', 2277);
+
+-------------------------------------------------------------------------------
+-- ST_Collect combiner
+-------------------------------------------------------------------------------
+
+INSERT INTO pipeline_combine VALUES (
+'pgis_geometry_collect_finalfn',
+'pgis_geometry_accum_transfn',
+'pgis_abs_send', 'pgis_abs_recv', 'pgis_geometry_accum_combinefn', 2277);
+
+-------------------------------------------------------------------------------
+-- ST_Polygonize combiner
+-------------------------------------------------------------------------------
+
+INSERT INTO pipeline_combine VALUES (
+'pgis_geometry_polygonize_finalfn',
+'pgis_geometry_accum_transfn',
+'pgis_abs_send', 'pgis_abs_recv', 'pgis_geometry_accum_combinefn', 2277);
+
+-------------------------------------------------------------------------------
+-- ST_MakeLine combiner
+-------------------------------------------------------------------------------
+
+INSERT INTO pipeline_combine VALUES (
+'pgis_geometry_makeline_finalfn',
+'pgis_geometry_accum_transfn',
+'pgis_abs_send', 'pgis_abs_recv', 'pgis_geometry_accum_combinefn', 2277);
+
+-------------------------------------------------------------------------------
+-- ST_CountAgg combiner
+-------------------------------------------------------------------------------
+
+CREATE OR REPLACE FUNCTION _st_countagg_combinefn(state agg_count, incoming agg_count)
+	RETURNS agg_count
+	AS $$
+	BEGIN
+		IF state IS NULL THEN
+			RETURN incoming;
+		END IF;
+
+		state.count := state.count + incoming.count;
+		RETURN state;
+	END
+	$$ LANGUAGE 'plpgsql' IMMUTABLE;
+
+-- The transition functions for each transition function's signature all have the same name,
+-- so we need to select each one individually in order to properly construct pipeline_combine entries
+INSERT INTO pipeline_combine VALUES (
+'_st_countagg_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_countagg_transfn' AND pronargs = 5),
+0, 0, '_st_countagg_combinefn',
+(SELECT oid FROM pg_type WHERE typname = 'agg_count'));
+
+INSERT INTO pipeline_combine VALUES (
+'_st_countagg_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_countagg_transfn' AND pronargs = 4),
+0, 0, '_st_countagg_combinefn',
+(SELECT oid FROM pg_type WHERE typname = 'agg_count'));
+
+INSERT INTO pipeline_combine VALUES (
+'_st_countagg_finalfn',
+(SELECT oid FROM pg_proc WHERE proname = '_st_countagg_transfn' AND pronargs = 3),
+0, 0, '_st_countagg_combinefn',
+(SELECT oid FROM pg_type WHERE typname = 'agg_count'));
+
+-------------------------------------------------------------------------------
+-- ST_SameAlignment combiner
+-------------------------------------------------------------------------------
+
+CREATE OR REPLACE FUNCTION _st_samealignment_combinefn(state agg_samealignment, incoming agg_samealignment)
+	RETURNS agg_samealignment
+	AS $$
+	BEGIN
+		IF state IS NULL THEN
+			RETURN incoming;
+		END IF;
+
+		state.aligned := ST_SameAlignment(state.refraster, incoming.refraster);
+
+		RETURN state;
+	END
+	$$ LANGUAGE 'plpgsql' IMMUTABLE;
+
+INSERT INTO pipeline_combine VALUES (
+'_st_samealignment_finalfn',
+'_st_samealignment_transfn',
+0, 0, '_st_samealignment_combinefn',
+(SELECT oid FROM pg_type WHERE typname = 'agg_samealignment'));
diff --git a/raster/rt_core/librtcore.h b/raster/rt_core/librtcore.h
index 0c33b991718..5274cd859a3 100644
--- a/raster/rt_core/librtcore.h
+++ b/raster/rt_core/librtcore.h
@@ -11,6 +11,7 @@
  * Copyright (C) 2009-2011 Mateusz Loskot <mateusz@loskot.net>
  * Copyright (C) 2008-2009 Sandro Santilli <strk@keybit.net>
  * Copyright (C) 2013 Nathaneil Hunter Clay <clay.nathaniel@gmail.com
+ * Portions Copyright 2013-2015 PipelineDB
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -823,13 +824,14 @@ rt_band_corrected_clamped_value(
  * @param cK : number of pixels counted thus far in coverage
  * @param cM : M component of 1-pass stddev for coverage
  * @param cQ : Q component of 1-pass stddev for coverage
+ * @param sum2: sum of the square of each input value, used for combining stddevs
  *
  * @return the summary statistics for a band or NULL
  */
 rt_bandstats rt_band_get_summary_stats(
 	rt_band band,
 	int exclude_nodata_value, double sample, int inc_vals,
-	uint64_t *cK, double *cM, double *cQ
+	uint64_t *cK, double *cM, double *cQ, double *sum2
 );
 	
 /**
@@ -2327,6 +2329,7 @@ struct rt_bandstats_t {
 	double min;
 	double max;
 	double sum;
+  double sum2;
 	double mean;
 	double stddev;
 
diff --git a/raster/rt_core/rt_statistics.c b/raster/rt_core/rt_statistics.c
index 974580cf1b0..329261a2a8e 100644
--- a/raster/rt_core/rt_statistics.c
+++ b/raster/rt_core/rt_statistics.c
@@ -10,6 +10,7 @@
  * Copyright (C) 2009-2011 Pierre Racine <pierre.racine@sbf.ulaval.ca>
  * Copyright (C) 2009-2011 Mateusz Loskot <mateusz@loskot.net>
  * Copyright (C) 2008-2009 Sandro Santilli <strk@keybit.net>
+ * Portions Copyright 2013-2015 PipelineDB
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -103,6 +104,7 @@ static void quicksort(double *left, double *right) {
  * @param cK : number of pixels counted thus far in coverage
  * @param cM : M component of 1-pass stddev for coverage
  * @param cQ : Q component of 1-pass stddev for coverage
+ * @param sum2: sum of the square of each input value, used for combining stddevs
  *
  * @return the summary statistics for a band or NULL
  */
@@ -110,7 +112,7 @@ rt_bandstats
 rt_band_get_summary_stats(
 	rt_band band,
 	int exclude_nodata_value, double sample, int inc_vals,
-	uint64_t *cK, double *cM, double *cQ
+	uint64_t *cK, double *cM, double *cQ, double *sum2
 ) {
 	uint32_t x = 0;
 	uint32_t y = 0;
@@ -322,6 +324,9 @@ rt_band_get_summary_stats(
 					}
 				}
 
+        if (sum2)
+          *sum2 += pow(value, 2);
+
 				/* min/max */
 				if (stats->count < 1) {
 					stats->count = 1;
diff --git a/raster/rt_pg/rtpg_mapalgebra.c b/raster/rt_pg/rtpg_mapalgebra.c
index 9dd039fcbd2..a93feabd6cd 100644
--- a/raster/rt_pg/rtpg_mapalgebra.c
+++ b/raster/rt_pg/rtpg_mapalgebra.c
@@ -11,6 +11,7 @@
  * Copyright (C) 2009-2011 Mateusz Loskot <mateusz@loskot.net>
  * Copyright (C) 2008-2009 Sandro Santilli <strk@keybit.net>
  * Copyright (C) 2013 Nathaniel Hunter Clay <clay.nathaniel@gmail.com>
+ * Portions Copyright 2013-2015 PipelineDB
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -45,6 +46,8 @@
 
 #include "rtpostgis.h"
 #include "rtpg_internal.h"
+#include "lib/stringinfo.h"
+#include "libpq/pqformat.h"
 
 /* n-raster MapAlgebra */
 Datum RASTER_nMapAlgebra(PG_FUNCTION_ARGS);
@@ -2052,6 +2055,489 @@ static int rtpg_union_noarg(rtpg_union_arg arg, rt_raster raster) {
 	return 1;
 }
 
+/*
+ * Serialize a rtpg_union_arg
+ */
+PG_FUNCTION_INFO_V1(unionargsend);
+Datum
+unionargsend(PG_FUNCTION_ARGS)
+{
+	MemoryContext context;
+	MemoryContext old;
+	StringInfoData buf;
+	rtpg_union_arg state = PG_GETARG_POINTER(0);
+	bytea *result;
+	int nbytes;
+	int i;
+	int j;
+
+	if (!AggCheckCallContext(fcinfo, &context))
+		context = fcinfo->flinfo->fn_mcxt;
+
+	old = MemoryContextSwitchTo(context);
+
+	initStringInfo(&buf);
+
+	/* Serialize each band's array of rasters */
+	pq_sendint(&buf, state->numband, sizeof(state->numband));
+	for (i=0; i<state->numband; i++)
+	{
+		pq_sendint(&buf, state->bandarg[i].nband, sizeof(state->bandarg[i].nband));
+		pq_sendint(&buf, state->bandarg[i].uniontype, sizeof(state->bandarg[i].uniontype));
+		pq_sendint(&buf, state->bandarg[i].numraster, sizeof(state->bandarg[i].numraster));
+
+		for (j=0; j<state->bandarg[i].numraster; j++)
+		{
+			uint32_t size;
+			rt_raster raster = state->bandarg[i].raster[j];
+			uint8_t *bytes = rt_raster_to_wkb(raster, false, &size);
+
+			pq_sendint(&buf, size, sizeof(size));
+			pq_sendbytes(&buf, (char *) bytes, size);
+		}
+	}
+
+	nbytes = buf.len - buf.cursor;
+	result = (bytea *) palloc0(nbytes + VARHDRSZ);
+	SET_VARSIZE(result, nbytes + VARHDRSZ);
+
+	pq_copymsgbytes(&buf, VARDATA(result), nbytes);
+
+	MemoryContextSwitchTo(old);
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+ * Deserialize a rtpg_union_arg
+ */
+PG_FUNCTION_INFO_V1(unionargrecv);
+Datum
+unionargrecv(PG_FUNCTION_ARGS)
+{
+	MemoryContext context;
+	MemoryContext old;
+	bytea *bytesin;
+	StringInfoData buf;
+	rtpg_union_arg result;
+	int nbytes;
+	int i;
+	int j;
+	int numband;
+
+	if (!AggCheckCallContext(fcinfo, &context))
+		context = fcinfo->flinfo->fn_mcxt;
+
+	old = MemoryContextSwitchTo(context);
+
+	bytesin = (bytea *) PG_GETARG_BYTEA_P(0);
+	nbytes =  VARSIZE(bytesin) - VARHDRSZ;
+
+	initStringInfo(&buf);
+	appendBinaryStringInfo(&buf, VARDATA(bytesin), nbytes);
+
+	numband = pq_getmsgint(&buf, sizeof(int));
+
+	result = palloc0(sizeof(struct rtpg_union_arg_t));
+	result->numband = numband;
+	result->bandarg = palloc0(numband * sizeof(struct rtpg_union_band_arg_t));
+
+	/* Read each band's array of rasters */
+	for (i=0; i<result->numband; i++)
+	{
+		result->bandarg[i].nband = pq_getmsgint(&buf, sizeof(result->bandarg[i].nband));
+		result->bandarg[i].uniontype = pq_getmsgint(&buf, sizeof(result->bandarg[i].uniontype));
+		result->bandarg[i].numraster = pq_getmsgint(&buf, sizeof(result->bandarg[i].numraster));
+		result->bandarg[i].raster = palloc0(result->bandarg[i].numraster * sizeof(rt_raster));
+
+		for (j=0; j<result->bandarg[i].numraster; j++)
+		{
+			uint32_t size = pq_getmsgint(&buf, sizeof(uint32_t));
+			const char *raw = pq_getmsgbytes(&buf, size);
+
+			result->bandarg[i].raster[j] = rt_raster_from_wkb((uint8_t *) raw, size);
+		}
+	}
+
+	MemoryContextSwitchTo(old);
+
+	PG_RETURN_POINTER(result);
+}
+
+static void
+raster_union(rtpg_union_arg iwr, rt_raster raster)
+{
+	rt_raster _raster = NULL;
+	rt_band _band = NULL;
+	int noerr = 1;
+	int isempty[2] = {0};
+	int hasband[2] = {0};
+	double _offset[4] = {0.};
+	int nbnodata = 0; /* 1 if adding bands */
+	int i = 0;
+	int j = 0;
+	int k = 0;
+	rt_iterator itrset;
+	rtpg_union_type utype = UT_LAST;
+	rt_pixtype pixtype = PT_END;
+	int hasnodata = 1;
+	double nodataval = 0;
+	rt_raster iraster = NULL;
+	rt_band iband = NULL;
+	int reuserast = 0;
+	int y = 0;
+	uint16_t _dim[2] = {0};
+	void *vals = NULL;
+	uint16_t nvals = 0;
+
+	POSTGIS_RT_DEBUG(3, "Starting...");
+
+	itrset = palloc(sizeof(struct rt_iterator_t) * 2);
+
+	/* by band to UNION */
+	for (i = 0; i < iwr->numband; i++) {
+
+		/* by raster */
+		for (j = 0; j < iwr->bandarg[i].numraster; j++) {
+			reuserast = 0;
+
+			/* type of union */
+			utype = iwr->bandarg[i].uniontype;
+
+			/* raster flags */
+			isempty[0] = rt_raster_is_empty(iwr->bandarg[i].raster[j]);
+			isempty[1] = rt_raster_is_empty(raster);
+
+			if (!isempty[0])
+				hasband[0] = rt_raster_has_band(iwr->bandarg[i].raster[j], 0);
+			if (!isempty[1])
+				hasband[1] = rt_raster_has_band(raster, iwr->bandarg[i].nband);
+
+			/* determine pixtype, hasnodata and nodataval */
+			_band = NULL;
+			if (!isempty[0] && hasband[0])
+				_band = rt_raster_get_band(iwr->bandarg[i].raster[j], 0);
+			else if (!isempty[1] && hasband[1])
+				_band = rt_raster_get_band(raster, iwr->bandarg[i].nband);
+			else {
+				pixtype = PT_64BF;
+				hasnodata = 1;
+				nodataval = rt_pixtype_get_min_value(pixtype);
+			}
+			if (_band != NULL) {
+				pixtype = rt_band_get_pixtype(_band);
+				hasnodata = 1;
+				if (rt_band_get_hasnodata_flag(_band))
+					rt_band_get_nodata(_band, &nodataval);
+				else
+					nodataval = rt_band_get_min_value(_band);
+			}
+
+			/* UT_MEAN and UT_RANGE require two passes */
+			/* UT_MEAN: first for UT_COUNT and second for UT_SUM */
+			if (iwr->bandarg[i].uniontype == UT_MEAN) {
+				/* first pass, UT_COUNT */
+				if (j < 1)
+					utype = UT_COUNT;
+				else
+					utype = UT_SUM;
+			}
+			/* UT_RANGE: first for UT_MIN and second for UT_MAX */
+			else if (iwr->bandarg[i].uniontype == UT_RANGE) {
+				/* first pass, UT_MIN */
+				if (j < 1)
+					utype = UT_MIN;
+				else
+					utype = UT_MAX;
+			}
+
+			/* force band settings for UT_COUNT */
+			if (utype == UT_COUNT) {
+				pixtype = PT_32BUI;
+				hasnodata = 0;
+				nodataval = 0;
+			}
+
+			POSTGIS_RT_DEBUGF(4, "(pixtype, hasnodata, nodataval) = (%s, %d, %f)", rt_pixtype_name(pixtype), hasnodata, nodataval);
+
+			/* set itrset */
+			itrset[0].raster = iwr->bandarg[i].raster[j];
+			itrset[0].nband = 0;
+			itrset[1].raster = raster;
+			itrset[1].nband = iwr->bandarg[i].nband;
+
+			/* allow use NODATA to replace missing bands */
+			if (nbnodata) {
+				itrset[0].nbnodata = 1;
+				itrset[1].nbnodata = 1;
+			}
+			/* missing bands are not ignored */
+			else {
+				itrset[0].nbnodata = 0;
+				itrset[1].nbnodata = 0;
+			}
+
+			/* if rasters AND bands are present, use copy approach */
+			if (!isempty[0] && !isempty[1] && hasband[0] && hasband[1]) {
+				POSTGIS_RT_DEBUG(3, "using line method");
+
+				/* generate empty out raster */
+				if (rt_raster_from_two_rasters(
+					iwr->bandarg[i].raster[j], raster,
+					ET_UNION,
+					&iraster, _offset
+				) != ES_NONE) {
+
+					pfree(itrset);
+					rtpg_union_arg_destroy(iwr);
+					if (raster != NULL) {
+						rt_raster_destroy(raster);
+					}
+
+					elog(ERROR, "RASTER_union_transfn: Could not create internal raster");
+				}
+				POSTGIS_RT_DEBUGF(4, "_offset = %f, %f, %f, %f",
+					_offset[0], _offset[1], _offset[2], _offset[3]);
+
+				/* rasters are spatially the same? */
+				if (
+					rt_raster_get_width(iwr->bandarg[i].raster[j]) == rt_raster_get_width(iraster) &&
+					rt_raster_get_height(iwr->bandarg[i].raster[j]) == rt_raster_get_height(iraster)
+				) {
+					double igt[6] = {0};
+					double gt[6] = {0};
+
+					rt_raster_get_geotransform_matrix(iwr->bandarg[i].raster[j], gt);
+					rt_raster_get_geotransform_matrix(iraster, igt);
+
+					reuserast = rt_util_same_geotransform_matrix(gt, igt);
+				}
+
+				/* use internal raster */
+				if (!reuserast) {
+					/* create band of same type */
+					if (rt_raster_generate_new_band(
+						iraster,
+						pixtype,
+						nodataval,
+						hasnodata, nodataval,
+						0
+					) == -1) {
+
+						pfree(itrset);
+						rtpg_union_arg_destroy(iwr);
+						rt_raster_destroy(iraster);
+						if (raster != NULL) {
+							rt_raster_destroy(raster);
+						}
+
+						elog(ERROR, "RASTER_union_transfn: Could not add new band to internal raster");
+					}
+					iband = rt_raster_get_band(iraster, 0);
+
+					/* copy working raster to output raster */
+					_dim[0] = rt_raster_get_width(iwr->bandarg[i].raster[j]);
+					_dim[1] = rt_raster_get_height(iwr->bandarg[i].raster[j]);
+					for (y = 0; y < _dim[1]; y++) {
+						POSTGIS_RT_DEBUGF(4, "Getting pixel line of working raster at (x, y, length) = (0, %d, %d)", y, _dim[0]);
+						if (rt_band_get_pixel_line(
+							_band,
+							0, y,
+							_dim[0],
+							&vals, &nvals
+						) != ES_NONE) {
+
+							pfree(itrset);
+							rtpg_union_arg_destroy(iwr);
+							rt_band_destroy(iband);
+							rt_raster_destroy(iraster);
+							if (raster != NULL) {
+								rt_raster_destroy(raster);
+							}
+
+							elog(ERROR, "RASTER_union_transfn: Could not get pixel line from band of working raster");
+						}
+
+						POSTGIS_RT_DEBUGF(4, "Setting pixel line at (x, y, length) = (%d, %d, %d)", (int) _offset[0], (int) _offset[1] + y, nvals);
+						if (rt_band_set_pixel_line(
+							iband,
+							(int) _offset[0], (int) _offset[1] + y,
+							vals, nvals
+						) != ES_NONE) {
+
+							pfree(itrset);
+							rtpg_union_arg_destroy(iwr);
+							rt_band_destroy(iband);
+							rt_raster_destroy(iraster);
+							if (raster != NULL) {
+								rt_raster_destroy(raster);
+							}
+
+							elog(ERROR, "RASTER_union_transfn: Could not set pixel line to band of internal raster");
+						}
+					}
+				}
+				else {
+					rt_raster_destroy(iraster);
+					iraster = iwr->bandarg[i].raster[j];
+					iband = rt_raster_get_band(iraster, 0);
+				}
+
+				/* run iterator for extent of input raster */
+				noerr = rt_raster_iterator(
+					itrset, 2,
+					ET_LAST, NULL,
+					pixtype,
+					hasnodata, nodataval,
+					0, 0,
+					NULL,
+					&utype,
+					rtpg_union_callback,
+					&_raster
+				);
+				if (noerr != ES_NONE) {
+
+					pfree(itrset);
+					rtpg_union_arg_destroy(iwr);
+					if (!reuserast) {
+						rt_band_destroy(iband);
+						rt_raster_destroy(iraster);
+					}
+					if (raster != NULL) {
+						rt_raster_destroy(raster);
+					}
+
+					elog(ERROR, "RASTER_union_transfn: Could not run raster iterator function");
+				}
+
+				/* with iterator raster, copy data to output raster */
+				_band = rt_raster_get_band(_raster, 0);
+				_dim[0] = rt_raster_get_width(_raster);
+				_dim[1] = rt_raster_get_height(_raster);
+				for (y = 0; y < _dim[1]; y++) {
+					POSTGIS_RT_DEBUGF(4, "Getting pixel line of iterator raster at (x, y, length) = (0, %d, %d)", y, _dim[0]);
+					if (rt_band_get_pixel_line(
+						_band,
+						0, y,
+						_dim[0],
+						&vals, &nvals
+					) != ES_NONE) {
+
+						pfree(itrset);
+						rtpg_union_arg_destroy(iwr);
+						if (!reuserast) {
+							rt_band_destroy(iband);
+							rt_raster_destroy(iraster);
+						}
+						if (raster != NULL) {
+							rt_raster_destroy(raster);
+						}
+
+						elog(ERROR, "RASTER_union_transfn: Could not get pixel line from band of working raster");
+					}
+
+					POSTGIS_RT_DEBUGF(4, "Setting pixel line at (x, y, length) = (%d, %d, %d)", (int) _offset[2], (int) _offset[3] + y, nvals);
+					if (rt_band_set_pixel_line(
+						iband,
+						(int) _offset[2], (int) _offset[3] + y,
+						vals, nvals
+					) != ES_NONE) {
+
+						pfree(itrset);
+						rtpg_union_arg_destroy(iwr);
+						if (!reuserast) {
+							rt_band_destroy(iband);
+							rt_raster_destroy(iraster);
+						}
+						if (raster != NULL) {
+							rt_raster_destroy(raster);
+						}
+
+						elog(ERROR, "RASTER_union_transfn: Could not set pixel line to band of internal raster");
+					}
+				}
+
+				/* free _raster */
+				rt_band_destroy(_band);
+				rt_raster_destroy(_raster);
+
+				/* replace working raster with output raster */
+				_raster = iraster;
+			}
+			else {
+				POSTGIS_RT_DEBUG(3, "using pixel method");
+
+				/* pass everything to iterator */
+				noerr = rt_raster_iterator(
+					itrset, 2,
+					ET_UNION, NULL,
+					pixtype,
+					hasnodata, nodataval,
+					0, 0,
+					NULL,
+					&utype,
+					rtpg_union_callback,
+					&_raster
+				);
+
+				if (noerr != ES_NONE) {
+
+					pfree(itrset);
+					rtpg_union_arg_destroy(iwr);
+					if (raster != NULL) {
+						rt_raster_destroy(raster);
+					}
+
+					elog(ERROR, "RASTER_union_transfn: Could not run raster iterator function");
+				}
+			}
+
+			/* replace working raster */
+			if (iwr->bandarg[i].raster[j] != NULL && !reuserast) {
+				for (k = rt_raster_get_num_bands(iwr->bandarg[i].raster[j]) - 1; k >= 0; k--)
+					rt_band_destroy(rt_raster_get_band(iwr->bandarg[i].raster[j], k));
+				rt_raster_destroy(iwr->bandarg[i].raster[j]);
+			}
+			iwr->bandarg[i].raster[j] = _raster;
+		}
+
+	}
+}
+
+/*
+ * Combines two rtpg_union_args into one
+ */
+PG_FUNCTION_INFO_V1(RASTER_union_combinefn);
+Datum RASTER_union_combinefn(PG_FUNCTION_ARGS)
+{
+	MemoryContext old;
+	MemoryContext aggcontext;
+	rtpg_union_arg state = PG_ARGISNULL(0) ? NULL : (rtpg_union_arg) PG_GETARG_POINTER(0);
+	rtpg_union_arg incoming = (rtpg_union_arg) PG_GETARG_POINTER(1);
+	int i;
+
+	if (!AggCheckCallContext(fcinfo, &aggcontext))
+		elog(ERROR, "_st_union_combinefn called in non-aggregate context");
+
+	if (state == NULL)
+		PG_RETURN_POINTER(incoming);
+
+	old = MemoryContextSwitchTo(aggcontext);
+
+	for (i=0; i<incoming->numband; i++)
+	{
+		int j;
+		for (j=0; j<incoming->bandarg[i].numraster; j++)
+		{
+			raster_union(state, incoming->bandarg[i].raster[j]);
+		}
+	}
+
+	MemoryContextSwitchTo(old);
+
+	PG_RETURN_POINTER(state);
+}
+
 /* UNION aggregate transition function */
 PG_FUNCTION_INFO_V1(RASTER_union_transfn);
 Datum RASTER_union_transfn(PG_FUNCTION_ARGS)
@@ -4273,7 +4759,7 @@ Datum RASTER_colorMap(PG_FUNCTION_ARGS)
 						if (arg->bandstats == NULL) {
 							POSTGIS_RT_DEBUG(4, "Getting band stats");
 							
-							arg->bandstats = rt_band_get_summary_stats(arg->band, 1, 1, 0, NULL, NULL, NULL);
+							arg->bandstats = rt_band_get_summary_stats(arg->band, 1, 1, 0, NULL, NULL, NULL, NULL);
 							if (arg->bandstats == NULL) {
 								pfree(_element);
 								rtpg_colormap_arg_destroy(arg);
diff --git a/raster/rt_pg/rtpg_statistics.c b/raster/rt_pg/rtpg_statistics.c
index 7192d7f98ff..98bc90acab4 100644
--- a/raster/rt_pg/rtpg_statistics.c
+++ b/raster/rt_pg/rtpg_statistics.c
@@ -11,6 +11,7 @@
  * Copyright (C) 2009-2011 Pierre Racine <pierre.racine@sbf.ulaval.ca>
  * Copyright (C) 2009-2011 Mateusz Loskot <mateusz@loskot.net>
  * Copyright (C) 2008-2009 Sandro Santilli <strk@keybit.net>
+ * Portions Copyright 2013-2015 PipelineDB
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -44,6 +45,8 @@
 #endif
 
 #include "rtpostgis.h"
+#include "lib/stringinfo.h"
+#include "libpq/pqformat.h"
 
 /* Get summary stats */
 Datum RASTER_summaryStats(PG_FUNCTION_ARGS);
@@ -138,7 +141,7 @@ Datum RASTER_summaryStats(PG_FUNCTION_ARGS)
 	}
 
 	/* we don't need the raw values, hence the zero parameter */
-	stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 0, NULL, NULL, NULL);
+	stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 0, NULL, NULL, NULL, NULL);
 	rt_band_destroy(band);
 	rt_raster_destroy(raster);
 	PG_FREE_IF_COPY(pgraster, 0);
@@ -373,7 +376,7 @@ Datum RASTER_summaryStatsCoverage(PG_FUNCTION_ARGS)
 		}
 
 		/* we don't need the raw values, hence the zero parameter */
-		stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 0, &cK, &cM, &cQ);
+		stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 0, &cK, &cM, &cQ, NULL);
 
 		rt_band_destroy(band);
 		rt_raster_destroy(raster);
@@ -546,6 +549,7 @@ rtpg_summarystats_arg_init() {
 	arg->stats->min = 0;
 	arg->stats->max = 0;
 	arg->stats->sum = 0;
+  arg->stats->sum2 = 0;
 	arg->stats->mean = 0;
 	arg->stats->stddev = -1;
 	arg->stats->values = NULL;
@@ -562,6 +566,164 @@ rtpg_summarystats_arg_init() {
 	return arg;
 }
 
+/*
+ * Serialize a rtpg_summarystats_arg
+ */
+PG_FUNCTION_INFO_V1(summarystatssend);
+Datum
+summarystatssend(PG_FUNCTION_ARGS)
+{
+	StringInfoData buf;
+	rtpg_summarystats_arg state = (rtpg_summarystats_arg) PG_GETARG_POINTER(0);
+	int i;
+	int nbytes;
+	int vlen;
+	bytea *result;
+
+	initStringInfo(&buf);
+
+	pq_sendint64(&buf, state->cK);
+	pq_sendfloat8(&buf, state->cM);
+	pq_sendfloat8(&buf, state->cQ);
+
+	pq_sendint(&buf, state->band_index, sizeof(state->band_index));
+	pq_sendint(&buf, state->exclude_nodata_value, 1);
+	pq_sendfloat8(&buf, state->sample);
+
+	pq_sendfloat8(&buf, state->stats->sample);
+	pq_sendint(&buf, state->stats->count, sizeof(state->stats->count));
+	pq_sendfloat8(&buf, state->stats->min);
+	pq_sendfloat8(&buf, state->stats->max);
+	pq_sendfloat8(&buf, state->stats->sum);
+	pq_sendfloat8(&buf, state->stats->sum2);
+	pq_sendfloat8(&buf, state->stats->mean);
+	pq_sendfloat8(&buf, state->stats->stddev);
+	pq_sendint(&buf, state->stats->sorted, sizeof(state->stats->sorted));
+
+	vlen = state->stats->values == NULL ? 0 : state->stats->count;
+	pq_sendint(&buf, vlen, sizeof(vlen));
+	for (i=0; i<vlen; i++)
+	{
+		pq_sendfloat8(&buf, state->stats->values[i]);
+	}
+
+	nbytes = buf.len - buf.cursor;
+	result = (bytea *) palloc(nbytes + VARHDRSZ);
+	SET_VARSIZE(result, nbytes + VARHDRSZ);
+
+	pq_copymsgbytes(&buf, VARDATA(result), nbytes);
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+ * Deserialize a rtpg_summarystats_arg
+ */
+PG_FUNCTION_INFO_V1(summarystatsrecv);
+Datum
+summarystatsrecv(PG_FUNCTION_ARGS)
+{
+	MemoryContext context;
+	MemoryContext old;
+	bytea *bytesin;
+	StringInfoData buf;
+	rtpg_summarystats_arg result;
+	int nbytes;
+	int vlen;
+
+	if (!AggCheckCallContext(fcinfo, &context))
+		context = fcinfo->flinfo->fn_mcxt;
+
+	old = MemoryContextSwitchTo(context);
+
+	bytesin = (bytea *) PG_GETARG_BYTEA_P(0);
+	nbytes = VARSIZE(bytesin) - VARHDRSZ;
+
+	initStringInfo(&buf);
+	appendBinaryStringInfo(&buf, VARDATA(bytesin), nbytes);
+
+	result = palloc0(sizeof(struct rtpg_summarystats_arg_t));
+
+	result->cK = pq_getmsgint64(&buf);
+	result->cM = pq_getmsgfloat8(&buf);
+	result->cQ = pq_getmsgfloat8(&buf);
+
+	result->band_index = pq_getmsgint(&buf, sizeof(result->band_index));
+	result->exclude_nodata_value = pq_getmsgint(&buf, 1);
+	result->sample = pq_getmsgfloat8(&buf);
+
+	result->stats = palloc0(sizeof(struct rt_bandstats_t));
+	result->stats->sample = pq_getmsgfloat8(&buf);
+	result->stats->count = pq_getmsgint(&buf, sizeof(result->stats->count));
+	result->stats->min = pq_getmsgfloat8(&buf);
+	result->stats->max = pq_getmsgfloat8(&buf);
+	result->stats->sum = pq_getmsgfloat8(&buf);
+	result->stats->sum2 = pq_getmsgfloat8(&buf);
+	result->stats->mean = pq_getmsgfloat8(&buf);
+	result->stats->stddev = pq_getmsgfloat8(&buf);
+	result->stats->sorted = pq_getmsgint(&buf, sizeof(result->stats->sorted));
+	result->stats->values = NULL;
+
+	vlen = pq_getmsgint(&buf, sizeof(vlen));
+	if (vlen > 0)
+	{
+		int i;
+
+		result->stats->values = palloc0(vlen * sizeof(double));
+		for (i=0; i<vlen; i++)
+		{
+			result->stats->values[i] = pq_getmsgfloat8(&buf);
+		}
+	}
+
+	MemoryContextSwitchTo(old);
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+ * Combines two rtpg_summarystats_args into one
+ */
+PG_FUNCTION_INFO_V1(RASTER_summaryStats_combinefn);
+Datum RASTER_summaryStats_combinefn(PG_FUNCTION_ARGS)
+{
+	MemoryContext old;
+	MemoryContext aggcontext;
+	rtpg_summarystats_arg state = PG_ARGISNULL(0) ? NULL : (rtpg_summarystats_arg) PG_GETARG_POINTER(0);
+	rtpg_summarystats_arg incoming = (rtpg_summarystats_arg) PG_GETARG_POINTER(1);
+	int n;
+	double s;
+	double s2;
+
+	if (!AggCheckCallContext(fcinfo, &aggcontext))
+		elog(ERROR, "_summaryStats_combinefn called in non-aggregate context");
+
+	if (state == NULL)
+		PG_RETURN_POINTER(incoming);
+
+	old = MemoryContextSwitchTo(aggcontext);
+
+	state->cK += incoming->cK;
+	state->cQ += incoming->cQ;
+	state->cM += incoming->cM;
+	state->stats->sum += incoming->stats->sum;
+	state->stats->sum2 += incoming->stats->sum2;
+	state->stats->count += incoming->stats->count;
+	state->stats->min = Min(state->stats->min, incoming->stats->min);
+	state->stats->max = Max(state->stats->max, incoming->stats->max);
+
+	n = state->stats->count;
+	s = state->stats->sum;
+	s2 = state->stats->sum2;
+
+	/* numerator of final stddev formula's radicand */
+	state->cQ = (((n * s2) - s * s) / n);
+
+	MemoryContextSwitchTo(old);
+
+	PG_RETURN_POINTER(state);
+}
+
 PG_FUNCTION_INFO_V1(RASTER_summaryStats_transfn);
 Datum RASTER_summaryStats_transfn(PG_FUNCTION_ARGS)
 {
@@ -775,7 +937,7 @@ Datum RASTER_summaryStats_transfn(PG_FUNCTION_ARGS)
 	stats = rt_band_get_summary_stats(
 		band, (int) state->exclude_nodata_value,
 		state->sample, 0,
-		&(state->cK), &(state->cM), &(state->cQ)
+		&(state->cK), &(state->cM), &(state->cQ), &(state->stats->sum2)
 	);
 
 	rt_band_destroy(band);
@@ -1097,7 +1259,7 @@ Datum RASTER_histogram(PG_FUNCTION_ARGS)
 		}
 
 		/* get stats */
-		stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 1, NULL, NULL, NULL);
+		stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 1, NULL, NULL, NULL, NULL);
 		rt_band_destroy(band);
 		rt_raster_destroy(raster);
 		PG_FREE_IF_COPY(pgraster, 0);
@@ -1562,7 +1724,7 @@ Datum RASTER_histogramCoverage(PG_FUNCTION_ARGS)
 			}
 
 			/* we need the raw values, hence the non-zero parameter */
-			stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 1, NULL, NULL, NULL);
+			stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 1, NULL, NULL, NULL, NULL);
 
 			rt_band_destroy(band);
 			rt_raster_destroy(raster);
@@ -1880,7 +2042,7 @@ Datum RASTER_quantile(PG_FUNCTION_ARGS)
 		}
 
 		/* get stats */
-		stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 1, NULL, NULL, NULL);
+		stats = rt_band_get_summary_stats(band, (int) exclude_nodata_value, sample, 1, NULL, NULL, NULL, NULL);
 		rt_band_destroy(band);
 		rt_raster_destroy(raster);
 		PG_FREE_IF_COPY(pgraster, 0);
diff --git a/raster/test/cunit/cu_band_stats.c b/raster/test/cunit/cu_band_stats.c
index cf153498709..8f358cbd398 100644
--- a/raster/test/cunit/cu_band_stats.c
+++ b/raster/test/cunit/cu_band_stats.c
@@ -4,6 +4,7 @@
  *
  * Copyright (C) 2012 Regents of the University of California
  *   <bkpark@ucdavis.edu>
+ * Portions Copyright 2013-2015 PipelineDB
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -60,7 +61,7 @@ static void test_band_stats() {
 	rt_band_get_nodata(band, &nodata);
 	CU_ASSERT_DOUBLE_EQUAL(nodata, 0, DBL_EPSILON);
 
-	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0, 1, NULL, NULL, NULL);
+	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0, 1, NULL, NULL, NULL, NULL);
 	CU_ASSERT(stats != NULL);
 	CU_ASSERT_DOUBLE_EQUAL(stats->min, 1, DBL_EPSILON);
 	CU_ASSERT_DOUBLE_EQUAL(stats->max, 198, DBL_EPSILON);
@@ -84,7 +85,7 @@ static void test_band_stats() {
 	rtdealloc(stats->values);
 	rtdealloc(stats);
 
-	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0.1, 1, NULL, NULL, NULL);
+	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0.1, 1, NULL, NULL, NULL, NULL);
 	CU_ASSERT(stats != NULL);
 
 	quantile = (rt_quantile) rt_band_get_quantiles(stats, NULL, 0, &count);
@@ -103,19 +104,19 @@ static void test_band_stats() {
 	rtdealloc(stats->values);
 	rtdealloc(stats);
 
-	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0.15, 0, NULL, NULL, NULL);
+	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0.15, 0, NULL, NULL, NULL, NULL);
 	CU_ASSERT(stats != NULL);
 	rtdealloc(stats);
 
-	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0.2, 0, NULL, NULL, NULL);
+	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0.2, 0, NULL, NULL, NULL, NULL);
 	CU_ASSERT(stats != NULL);
 	rtdealloc(stats);
 
-	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0.25, 0, NULL, NULL, NULL);
+	stats = (rt_bandstats) rt_band_get_summary_stats(band, 1, 0.25, 0, NULL, NULL, NULL, NULL);
 	CU_ASSERT(stats != NULL);
 	rtdealloc(stats);
 
-	stats = (rt_bandstats) rt_band_get_summary_stats(band, 0, 0, 1, NULL, NULL, NULL);
+	stats = (rt_bandstats) rt_band_get_summary_stats(band, 0, 0, 1, NULL, NULL, NULL, NULL);
 	CU_ASSERT(stats != NULL);
 	CU_ASSERT_DOUBLE_EQUAL(stats->min, 0, DBL_EPSILON);
 	CU_ASSERT_DOUBLE_EQUAL(stats->max, 198, DBL_EPSILON);
@@ -127,7 +128,7 @@ static void test_band_stats() {
 	rtdealloc(stats->values);
 	rtdealloc(stats);
 
-	stats = (rt_bandstats) rt_band_get_summary_stats(band, 0, 0.1, 1, NULL, NULL, NULL);
+	stats = (rt_bandstats) rt_band_get_summary_stats(band, 0, 0.1, 1, NULL, NULL, NULL, NULL);
 	CU_ASSERT(stats != NULL);
 
 	quantile = (rt_quantile) rt_band_get_quantiles(stats, NULL, 0, &count);
diff --git a/topology/topology.sql.in b/topology/topology.sql.in
index e7601230d69..7cc66547461 100644
--- a/topology/topology.sql.in
+++ b/topology/topology.sql.in
@@ -6,6 +6,7 @@
 --
 -- Copyright (C) 2010, 2011 Sandro Santilli <strk@keybit.net>
 -- Copyright (C) 2005 Refractions Research Inc.
+-- Portions Copyright 2013-2015 PipelineDB
 --
 -- This is free software; you can redistribute and/or modify it under
 -- the terms of the GNU General Public Licence. See the COPYING file.
@@ -2012,4 +2013,28 @@ CREATE OR REPLACE FUNCTION topology.postgis_topology_scripts_installed() RETURNS
 -- Make sure topology is in database search path --
 SELECT topology.AddToSearchPath('topology');
 
+-------------------------------------------------------------------------------
+-- TopoElementArray_agg combiner
+-------------------------------------------------------------------------------
+
+CREATE OR REPLACE FUNCTION topology.TopoElementArray_combine(state topology.TopoElementArray, incoming topology.TopoElementArray)
+	RETURNS topology.TopoElementArray
+	AS $$
+	BEGIN
+		IF state IS NULL THEN
+			RETURN incoming;
+		END IF;
+
+		state := state::int[][] || incoming::int[][];
+
+		RETURN state;
+	END
+	$$ LANGUAGE 'plpgsql' IMMUTABLE;
+
+INSERT INTO pipeline_combine VALUES (
+0,
+'topology.TopoElementArray_append',
+0, 0, 'topology.TopoElementArray_combine',
+(SELECT oid FROM pg_type WHERE typname = 'topoelementarray'));
+
 COMMIT;