diff --git a/gluon/dal/adapters/postgres.py b/gluon/dal/adapters/postgres.py
index 7e8c32fd..6694ae0b 100644
--- a/gluon/dal/adapters/postgres.py
+++ b/gluon/dal/adapters/postgres.py
@@ -278,6 +278,12 @@ class PostgreSQLAdapter(BaseAdapter):
         """
         return 'ST_Simplify(%s,%s)' %(self.expand(first), self.expand(second, 'double'))
 
+    def ST_SIMPLIFYPRESERVETOPOLOGY(self, first, second):
+        """
+        http://postgis.org/docs/ST_SimplifyPreserveTopology.html
+        """
+        return 'ST_SimplifyPreserveTopology(%s,%s)' %(self.expand(first), self.expand(second, 'double'))
+
     def ST_TOUCHES(self, first, second):
         """
         http://postgis.org/docs/ST_Touches.html
diff --git a/gluon/dal/objects.py b/gluon/dal/objects.py
index 9c22449a..7c4cb03f 100644
--- a/gluon/dal/objects.py
+++ b/gluon/dal/objects.py
@@ -1304,6 +1304,10 @@ class Expression(object):
         db = self.db
         return Expression(db, db._adapter.ST_SIMPLIFY, self, value, self.type)
 
+    def st_simplifypreservetopology(self, value):
+        db = self.db
+        return Expression(db, db._adapter.ST_SIMPLIFYPRESERVETOPOLOGY, self, value, self.type)
+
     # GIS queries
 
     def st_contains(self, value):