diff --git a/include/mapnik/image_reader.hpp b/include/mapnik/image_reader.hpp
index bb8d30198..bda9b735e 100644
--- a/include/mapnik/image_reader.hpp
+++ b/include/mapnik/image_reader.hpp
@@ -53,6 +53,7 @@ struct MAPNIK_DECL image_reader
 {
     virtual unsigned width() const=0;
     virtual unsigned height() const=0;
+    virtual bool premultiplied_alpha() const=0;
     virtual void read(unsigned x,unsigned y,image_data_32& image)=0;
     virtual ~image_reader() {}
 };
diff --git a/include/mapnik/json/geometry_generator_grammar.hpp b/include/mapnik/json/geometry_generator_grammar.hpp
index a1915b062..408bbf212 100644
--- a/include/mapnik/json/geometry_generator_grammar.hpp
+++ b/include/mapnik/json/geometry_generator_grammar.hpp
@@ -26,7 +26,7 @@
 // mapnik
 #include <mapnik/global.hpp>
 #include <mapnik/geometry.hpp>
-#include <mapnik/util/vertex_iterator.hpp>
+#include <mapnik/util/path_iterator.hpp>
 #include <mapnik/util/container_adapter.hpp>
 
 // boost
@@ -137,14 +137,14 @@ struct geometry_generator_grammar :
         using boost::spirit::karma::_r1;
         using boost::spirit::karma::eps;
         using boost::spirit::karma::string;
-        
+
         coordinates =  point | linestring | polygon
             ;
-        
+
         point = &uint_(mapnik::Point)[_1 = _type(_val)]
             << point_coord [_1 = _first(_val)]
             ;
-        
+
         linestring = &uint_(mapnik::LineString)[_1 = _type(_val)]
             << lit('[')
             << coords
@@ -156,13 +156,13 @@ struct geometry_generator_grammar :
             << coords2
             << lit("]]")
             ;
-        
-        point_coord = &uint_ 
-            << lit('[') 
+
+        point_coord = &uint_
+            << lit('[')
             << coord_type << lit(',') << coord_type
             << lit("]")
             ;
-        
+
         polygon_coord %= ( &uint_(mapnik::SEG_MOVETO) << eps[_r1 += 1]
                            << string[ if_ (_r1 > 1) [_1 = "],["]
                                       .else_[_1 = '[' ]] | &uint_ << lit(','))
@@ -170,25 +170,25 @@ struct geometry_generator_grammar :
             << lit(',')
             << coord_type << lit(']')
             ;
-        
+
         coords2 %= *polygon_coord(_a)
             ;
-        
+
         coords = point_coord % lit(',')
             ;
-        
+
     }
     // rules
     karma::rule<OutputIterator, geometry_type const& ()> coordinates;
     karma::rule<OutputIterator, geometry_type const& ()> point;
     karma::rule<OutputIterator, geometry_type const& ()> linestring;
     karma::rule<OutputIterator, geometry_type const& ()> polygon;
-    
+
     karma::rule<OutputIterator, geometry_type const& ()> coords;
     karma::rule<OutputIterator, karma::locals<unsigned>, geometry_type const& ()> coords2;
     karma::rule<OutputIterator, geometry_type::value_type ()> point_coord;
     karma::rule<OutputIterator, geometry_type::value_type (unsigned& )> polygon_coord;
-    
+
     // phoenix functions
     phoenix::function<get_type > _type;
     phoenix::function<get_first> _first;
@@ -200,7 +200,7 @@ struct geometry_generator_grammar :
 
 template <typename OutputIterator>
 struct multi_geometry_generator_grammar :
-        karma::grammar<OutputIterator, karma::locals<boost::tuple<unsigned,bool> >, 
+        karma::grammar<OutputIterator, karma::locals<boost::tuple<unsigned,bool> >,
                        geometry_container const& ()>
 {
 
@@ -223,36 +223,36 @@ struct multi_geometry_generator_grammar :
             (mapnik::LineString + 3,"\"MultiLineString\"")
             (mapnik::Polygon + 3,"\"MultiPolygon\"")
             ;
-        
-        start %= ( eps(phoenix::at_c<1>(_a))[_a = _multi_type(_val)] 
+
+        start %= ( eps(phoenix::at_c<1>(_a))[_a = _multi_type(_val)]
                    << lit("{\"type\":\"GeometryCollection\",\"geometries\":[")
                    << geometry_collection << lit("]}")
                    |
-                   geometry)              
+                   geometry)
             ;
-         
+
         geometry_collection = -(geometry2 % lit(','))
             ;
-        
-        geometry = (lit("{\"type\":") 
-                    << geometry_types[_1 = phoenix::at_c<0>(_a)][_a = _multi_type(_val)] 
+
+        geometry = (lit("{\"type\":")
+                    << geometry_types[_1 = phoenix::at_c<0>(_a)][_a = _multi_type(_val)]
                     << lit(",\"coordinates\":")
                     << string[ if_ (phoenix::at_c<0>(_a) > 3) [_1 = '[']]
                     << coordinates
                     << string[ if_ (phoenix::at_c<0>(_a) > 3) [_1 = ']']]
-                    << lit('}')) | lit("null")       
+                    << lit('}')) | lit("null")
             ;
-        
-        geometry2 = lit("{\"type\":") 
+
+        geometry2 = lit("{\"type\":")
             << geometry_types[_1 = _a][_a = type_(_val)]
             << lit(",\"coordinates\":")
             << path
-            << lit('}') 
+            << lit('}')
             ;
-        
+
         coordinates %= path % lit(',')
             ;
-        
+
     }
     // rules
     karma::rule<OutputIterator, karma::locals<boost::tuple<unsigned,bool> >,
diff --git a/include/mapnik/raster.hpp b/include/mapnik/raster.hpp
index d48cf6bd0..2a9951966 100644
--- a/include/mapnik/raster.hpp
+++ b/include/mapnik/raster.hpp
@@ -32,11 +32,13 @@ struct raster
 {
     box2d<double> ext_;
     image_data_32 data_;
-    raster(box2d<double> const& ext,image_data_32 const& data)
+    bool premultiplied_alpha_;
+    raster(box2d<double> const& ext,image_data_32 const& data, bool premultiplied_alpha = false)
         : ext_(ext),
-          data_(data) {}
+          data_(data),
+          premultiplied_alpha_(premultiplied_alpha)
+    {}
 };
 }
 
 #endif // MAPNIK_RASTER_HPP
-
diff --git a/include/mapnik/simplify_converter.hpp b/include/mapnik/simplify_converter.hpp
index 83e9a0235..2476311d2 100644
--- a/include/mapnik/simplify_converter.hpp
+++ b/include/mapnik/simplify_converter.hpp
@@ -17,7 +17,8 @@
 namespace mapnik
 {
 
-struct weighted_vertex : private boost::noncopyable {
+struct weighted_vertex : private boost::noncopyable
+{
     vertex2d coord;
     double weight;
     weighted_vertex *prev;
@@ -27,20 +28,23 @@ struct weighted_vertex : private boost::noncopyable {
         coord(coord_),
         weight(std::numeric_limits<double>::infinity()),
         prev(NULL),
-        next(NULL) { }
+        next(NULL) {}
 
-    double nominalWeight() {
+    double nominalWeight()
+    {
         if (prev == NULL || next == NULL || coord.cmd != SEG_LINETO) {
             return std::numeric_limits<double>::infinity();
         }
-        vertex2d& A = prev->coord;
-        vertex2d& B = next->coord;
-        vertex2d& C = coord;
+        vertex2d const& A = prev->coord;
+        vertex2d const& B = next->coord;
+        vertex2d const& C = coord;
         return std::abs((double)((A.x - C.x) * (B.y - A.y) - (A.x - B.x) * (C.y - A.y))) / 2.0;
     }
 
-    struct ascending_sort {
-        bool operator() (const weighted_vertex *a, const weighted_vertex *b) {
+    struct ascending_sort
+    {
+        bool operator() (const weighted_vertex *a, const weighted_vertex *b)
+        {
             return b->weight > a->weight;
         }
     };
@@ -97,10 +101,11 @@ struct MAPNIK_DECL simplify_converter
 {
 public:
     simplify_converter(Geometry& geom)
-        : geom_(geom)
-        , tolerance_(0.0)
-        , status_(initial)
-        , algorithm_(radial_distance)
+        : geom_(geom),
+        tolerance_(0.0),
+        status_(initial),
+        algorithm_(radial_distance),
+        pos_(0)
     {}
 
     enum status
@@ -117,8 +122,10 @@ public:
         return algorithm_;
     }
 
-    void set_simplify_algorithm(simplify_algorithm_e value) {
-        if (algorithm_ != value) {
+    void set_simplify_algorithm(simplify_algorithm_e value)
+    {
+        if (algorithm_ != value)
+        {
             algorithm_ = value;
             reset();
         }
@@ -145,7 +152,7 @@ public:
         pos_ = 0;
     }
 
-    void rewind(unsigned int)
+    void rewind(unsigned int) const
     {
         pos_ = 0;
     }
@@ -360,7 +367,8 @@ private:
         }
     }
 
-    status init_vertices_visvalingam_whyatt() {
+    status init_vertices_visvalingam_whyatt()
+    {
         typedef std::set<weighted_vertex *, weighted_vertex::ascending_sort> VertexSet;
         typedef std::vector<weighted_vertex *> VertexList;
 
@@ -371,13 +379,13 @@ private:
             v_list.push_back(new weighted_vertex(vtx));
         }
 
-        if (!v_list.size()) {
+        if (v_list.empty()) {
             return status_ = process;
         }
 
         // Connect the vertices in a linked list and insert them into the set.
         VertexSet v;
-        for (VertexList::iterator i = v_list.begin(); i != v_list.end(); i++)
+        for (VertexList::iterator i = v_list.begin(); i != v_list.end(); ++i)
         {
             (*i)->prev = i == v_list.begin() ? NULL : *(i - 1);
             (*i)->next = i + 1 == v_list.end() ? NULL : *(i + 1);
@@ -415,9 +423,10 @@ private:
         v.clear();
 
         // Traverse the remaining list and insert them into the vertex cache.
-        for (VertexList::iterator i = v_list.begin(); i != v_list.end(); i++)
+        for (VertexList::iterator i = v_list.begin(); i != v_list.end(); ++i)
         {
-            if ((*i)->weight >= tolerance_) {
+            if ((*i)->weight >= tolerance_)
+            {
                 vertices_.push_back((*i)->coord);
             }
             delete *i;
@@ -431,10 +440,10 @@ private:
     double                          tolerance_;
     status                          status_;
     simplify_algorithm_e            algorithm_;
-    size_t                          pos_;
     std::deque<vertex2d>            vertices_;
     std::deque<vertex2d>            sleeve_cont_;
     vertex2d                        previous_vertex_;
+    mutable size_t                  pos_;
 };
 
 
diff --git a/include/mapnik/util/container_adapter.hpp b/include/mapnik/util/container_adapter.hpp
index 2cac51f28..ae985a837 100644
--- a/include/mapnik/util/container_adapter.hpp
+++ b/include/mapnik/util/container_adapter.hpp
@@ -26,7 +26,7 @@
 // mapnik
 #include <mapnik/global.hpp>
 #include <mapnik/geometry.hpp>
-#include <mapnik/util/vertex_iterator.hpp>
+#include <mapnik/util/path_iterator.hpp>
 
 // boost
 #include <boost/tuple/tuple.hpp>
@@ -40,26 +40,26 @@ struct is_container<mapnik::geometry_type const> : mpl::true_ {} ;
 template <>
 struct container_iterator<mapnik::geometry_type const>
 {
-    typedef mapnik::util::vertex_iterator<double> type;
+    typedef mapnik::util::path_iterator<mapnik::geometry_type> type;
 };
 
 template <>
 struct begin_container<mapnik::geometry_type const>
 {
-    static mapnik::util::vertex_iterator<double>
+    static mapnik::util::path_iterator<mapnik::geometry_type>
     call (mapnik::geometry_type const& g)
     {
-        return mapnik::util::vertex_iterator<double>(g.data());
+        return mapnik::util::path_iterator<mapnik::geometry_type>(g);
     }
 };
 
 template <>
 struct end_container<mapnik::geometry_type const>
 {
-    static mapnik::util::vertex_iterator<double>
+    static mapnik::util::path_iterator<mapnik::geometry_type>
     call (mapnik::geometry_type const& g)
     {
-        return mapnik::util::vertex_iterator<double>();
+        return mapnik::util::path_iterator<mapnik::geometry_type>();
     }
 };
 
diff --git a/include/mapnik/util/geometry_svg_generator.hpp b/include/mapnik/util/geometry_svg_generator.hpp
index 11a7994b0..b229e73c1 100644
--- a/include/mapnik/util/geometry_svg_generator.hpp
+++ b/include/mapnik/util/geometry_svg_generator.hpp
@@ -26,7 +26,7 @@
 // mapnik
 #include <mapnik/global.hpp>
 #include <mapnik/geometry.hpp>
-#include <mapnik/util/vertex_iterator.hpp>
+#include <mapnik/util/path_iterator.hpp>
 #include <mapnik/util/container_adapter.hpp>
 
 // boost
diff --git a/include/mapnik/util/geometry_to_svg.hpp b/include/mapnik/util/geometry_to_svg.hpp
index 018545cc9..d65d14d6c 100644
--- a/include/mapnik/util/geometry_to_svg.hpp
+++ b/include/mapnik/util/geometry_to_svg.hpp
@@ -26,7 +26,6 @@
 // mapnik
 #include <mapnik/global.hpp>
 #include <mapnik/geometry.hpp>
-#include <mapnik/util/vertex_iterator.hpp>
 #include <mapnik/util/geometry_svg_generator.hpp>
 
 // boost
diff --git a/include/mapnik/util/geometry_to_wkb.hpp b/include/mapnik/util/geometry_to_wkb.hpp
index 3b0159345..ee3686568 100644
--- a/include/mapnik/util/geometry_to_wkb.hpp
+++ b/include/mapnik/util/geometry_to_wkb.hpp
@@ -126,8 +126,8 @@ namespace mapnik { namespace util {
         ss.write(reinterpret_cast<char*>(&byte_order),1);
         int type = static_cast<int>(mapnik::Point);
         write(ss,type,4,byte_order);
-        double x(0);
-        double y(0);
+        double x = 0;
+        double y = 0;
         g.vertex(0,&x,&y);
         write(ss,x,8,byte_order);
         write(ss,y,8,byte_order);
@@ -146,8 +146,8 @@ namespace mapnik { namespace util {
         int type = static_cast<int>(mapnik::LineString);
         write(ss,type,4,byte_order);
         write(ss,num_points,4,byte_order);
-        double x(0);
-        double y(0);
+        double x = 0;
+        double y = 0;
         for (unsigned i=0; i< num_points; ++i)
         {
             g.vertex(i,&x,&y);
@@ -167,8 +167,8 @@ namespace mapnik { namespace util {
         typedef std::vector<point_type> linear_ring;
         boost::ptr_vector<linear_ring> rings;
 
-        double x(0);
-        double y(0);
+        double x = 0;
+        double y = 0;
         std::size_t size = 1 + 4 + 4 ; // byteOrder + wkbType + numRings
         for (unsigned i=0; i< num_points; ++i)
         {
diff --git a/include/mapnik/util/geometry_to_wkt.hpp b/include/mapnik/util/geometry_to_wkt.hpp
index bd7e0268b..e49423ece 100644
--- a/include/mapnik/util/geometry_to_wkt.hpp
+++ b/include/mapnik/util/geometry_to_wkt.hpp
@@ -26,7 +26,6 @@
 // mapnik
 #include <mapnik/global.hpp>
 #include <mapnik/geometry.hpp>
-#include <mapnik/util/vertex_iterator.hpp>
 #include <mapnik/util/geometry_wkt_generator.hpp>
 
 // boost
@@ -40,7 +39,7 @@ bool to_wkt(std::string & wkt, mapnik::geometry_type const& geom)
 {
     typedef std::back_insert_iterator<std::string> sink_type;
     sink_type sink(wkt);
-    wkt_generator<sink_type> generator(true);
+    wkt_generator<sink_type, mapnik::geometry_type> generator(true);
     bool result = karma::generate(sink, generator, geom);
     return result;
 }
@@ -49,7 +48,7 @@ bool to_wkt(std::string & wkt, mapnik::geometry_container const& geom)
 {
     typedef std::back_insert_iterator<std::string> sink_type;
     sink_type sink(wkt);
-    wkt_multi_generator<sink_type> generator;
+    wkt_multi_generator<sink_type, mapnik::geometry_container> generator;
     bool result = karma::generate(sink, generator, geom);
     return result;
 }
diff --git a/include/mapnik/util/geometry_wkt_generator.hpp b/include/mapnik/util/geometry_wkt_generator.hpp
index e2c4eb220..ee75c3dbd 100644
--- a/include/mapnik/util/geometry_wkt_generator.hpp
+++ b/include/mapnik/util/geometry_wkt_generator.hpp
@@ -25,7 +25,6 @@
 
 // mapnik
 #include <mapnik/global.hpp>
-#include <mapnik/geometry.hpp>
 
 // boost
 #include <boost/tuple/tuple.hpp>
@@ -36,7 +35,7 @@
 #include <boost/spirit/include/phoenix_function.hpp>
 #include <boost/spirit/home/phoenix/statement/if.hpp>
 #include <boost/fusion/include/boost_tuple.hpp>
-
+#include <boost/type_traits/remove_pointer.hpp>
 
 //#define BOOST_SPIRIT_USE_PHOENIX_V3 1
 
@@ -50,7 +49,6 @@ struct is_container<mapnik::geometry_container>
 
 }}}
 
-
 namespace mapnik { namespace util {
 
 namespace karma = boost::spirit::karma;
@@ -58,34 +56,41 @@ namespace phoenix = boost::phoenix;
 
 namespace detail {
 
+template <typename Geometry>
 struct get_type
 {
     template <typename T>
     struct result { typedef int type; };
 
-    int operator() (geometry_type const& geom) const
+    int operator() (Geometry const& geom) const
     {
         return static_cast<int>(geom.type());
     }
 };
 
+template <typename T>
 struct get_first
 {
-    template <typename T>
-    struct result { typedef geometry_type::value_type const type; };
+    typedef T geometry_type;
 
-    geometry_type::value_type const operator() (geometry_type const& geom) const
+    template <typename U>
+    struct result { typedef typename geometry_type::value_type const type; };
+
+    typename geometry_type::value_type const operator() (geometry_type const& geom) const
     {
-        geometry_type::value_type coord;
-        boost::get<0>(coord) = geom.vertex(0,&boost::get<1>(coord),&boost::get<2>(coord));
+        typename geometry_type::value_type coord;
+        geom.rewind(0);
+        boost::get<0>(coord) = geom.vertex(&boost::get<1>(coord),&boost::get<2>(coord));
         return coord;
     }
 };
 
-
+template <typename T>
 struct multi_geometry_
 {
-    template <typename T>
+    typedef T geometry_container;
+
+    template <typename U>
     struct result { typedef bool type; };
 
     bool operator() (geometry_container const& geom) const
@@ -94,9 +99,12 @@ struct multi_geometry_
     }
 };
 
+template <typename T>
 struct multi_geometry_type
 {
-    template <typename T>
+    typedef T geometry_container;
+
+    template <typename U>
     struct result { typedef boost::tuple<unsigned,bool> type; };
 
     boost::tuple<unsigned,bool> operator() (geometry_container const& geom) const;
@@ -113,10 +121,13 @@ struct wkt_coordinate_policy : karma::real_policies<T>
 
 }
 
-template <typename OutputIterator>
+template <typename OutputIterator, typename Geometry>
 struct wkt_generator :
-    karma::grammar<OutputIterator, geometry_type const& ()>
+    karma::grammar<OutputIterator, Geometry const& ()>
 {
+    typedef Geometry geometry_type;
+    typedef typename boost::remove_pointer<typename geometry_type::value_type>::type coord_type;
+
     wkt_generator(bool single = false);
     // rules
     karma::rule<OutputIterator, geometry_type const& ()> wkt;
@@ -126,33 +137,35 @@ struct wkt_generator :
 
     karma::rule<OutputIterator, geometry_type const& ()> coords;
     karma::rule<OutputIterator, karma::locals<unsigned>, geometry_type const& ()> coords2;
-    karma::rule<OutputIterator, geometry_type::value_type ()> point_coord;
-    karma::rule<OutputIterator, geometry_type::value_type (unsigned& )> polygon_coord;
+    karma::rule<OutputIterator, coord_type ()> point_coord;
+    karma::rule<OutputIterator, coord_type (unsigned& )> polygon_coord;
 
     // phoenix functions
-    phoenix::function<detail::get_type > _type;
-    phoenix::function<detail::get_first> _first;
+    phoenix::function<detail::get_type<geometry_type> > _type;
+    phoenix::function<detail::get_first<geometry_type> > _first;
     //
-    karma::real_generator<double, detail::wkt_coordinate_policy<double> > coord_type;
+    karma::real_generator<double, detail::wkt_coordinate_policy<double> > coordinate;
 };
 
 
-template <typename OutputIterator>
+template <typename OutputIterator, typename GeometryContainer>
 struct wkt_multi_generator :
-        karma::grammar<OutputIterator, karma::locals< boost::tuple<unsigned,bool> >, geometry_container const& ()>
+        karma::grammar<OutputIterator, karma::locals< boost::tuple<unsigned,bool> >, GeometryContainer const& ()>
 {
+    typedef GeometryContainer geometry_contaner;
+    typedef boost::remove_pointer<typename geometry_container::value_type>::type geometry_type;
 
     wkt_multi_generator();
     // rules
-    karma::rule<OutputIterator, karma::locals<boost::tuple<unsigned,bool> >, geometry_container const& ()> wkt;
-    karma::rule<OutputIterator, geometry_container const& ()> geometry;
+    karma::rule<OutputIterator, karma::locals<boost::tuple<unsigned,bool> >, GeometryContainer const& ()> wkt;
+    karma::rule<OutputIterator, GeometryContainer const& ()> geometry;
     karma::rule<OutputIterator, geometry_type const& ()> single_geometry;
-    karma::rule<OutputIterator, geometry_container const& ()> multi_geometry;
-    wkt_generator<OutputIterator>  path;
+    karma::rule<OutputIterator, GeometryContainer const& ()> multi_geometry;
+    wkt_generator<OutputIterator, geometry_type >  path;
     // phoenix
-    phoenix::function<detail::multi_geometry_> is_multi;
-    phoenix::function<detail::multi_geometry_type> _multi_type;
-    phoenix::function<detail::get_type > _type;
+    phoenix::function<detail::multi_geometry_<GeometryContainer> > is_multi;
+    phoenix::function<detail::multi_geometry_type<GeometryContainer> > _multi_type;
+    phoenix::function<detail::get_type<geometry_type> > _type;
     //
     karma::symbols<unsigned, char const*> geometry_types;
 };
diff --git a/include/mapnik/util/path_iterator.hpp b/include/mapnik/util/path_iterator.hpp
new file mode 100644
index 000000000..f62624ab5
--- /dev/null
+++ b/include/mapnik/util/path_iterator.hpp
@@ -0,0 +1,85 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2011 Artem Pavlenko
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *****************************************************************************/
+
+#ifndef MAPNIK_VERTEX_ITERATOR_HPP
+#define MAPNIK_VERTEX_ITERATOR_HPP
+
+// mapnik
+#include <mapnik/global.hpp>
+
+// boost
+#include <boost/tuple/tuple.hpp>
+#include <boost/iterator/iterator_facade.hpp>
+
+namespace mapnik { namespace util {
+
+template <typename T>
+class path_iterator
+    : public boost::iterator_facade< path_iterator<T>,
+                                     boost::tuple<unsigned,double,double> const,
+                                     boost::forward_traversal_tag
+                                     >
+{
+
+public:
+    typedef T path_type;
+    typedef typename boost::tuple<unsigned, double, double> value_type;
+
+    path_iterator()
+        : v_(mapnik::SEG_END,0,0),
+          vertices_()
+    {}
+
+    explicit path_iterator(path_type const& vertices)
+        : vertices_(&vertices)
+    {
+        vertices_->rewind(0);
+        increment();
+    }
+
+private:
+    friend class boost::iterator_core_access;
+
+    void increment()
+    {
+        boost::get<0>(v_) = vertices_->vertex( &boost::get<1>(v_), &boost::get<2>(v_));
+    }
+
+    bool equal( path_iterator const& other) const
+    {
+        return boost::get<0>(v_) == boost::get<0>(other.v_);
+    }
+
+    value_type const& dereference() const
+    {
+        return v_;
+    }
+
+    value_type v_;
+    const path_type *vertices_;
+    unsigned pos_;
+};
+
+}}
+
+
+#endif // MAPNIK_VERTEX_ITERATOR_HPP
diff --git a/include/mapnik/util/vertex_iterator.hpp b/include/mapnik/util/vertex_iterator.hpp
deleted file mode 100644
index 5cc794078..000000000
--- a/include/mapnik/util/vertex_iterator.hpp
+++ /dev/null
@@ -1,87 +0,0 @@
-/*****************************************************************************
- *
- * This file is part of Mapnik (c++ mapping toolkit)
- *
- * Copyright (C) 2011 Artem Pavlenko
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- *
- *****************************************************************************/
-
-#ifndef MAPNIK_VERTEX_ITERATOR_HPP
-#define MAPNIK_VERTEX_ITERATOR_HPP
-
-// mapnik
-#include <mapnik/global.hpp>
-#include <mapnik/vertex_vector.hpp>
-
-// boost
-#include <boost/tuple/tuple.hpp>
-#include <boost/iterator/iterator_facade.hpp>
-
-namespace mapnik { namespace util {
-
-    template <typename T>
-    class vertex_iterator
-        : public boost::iterator_facade< vertex_iterator<T>,
-                                         typename boost::tuple<unsigned,T,T> const,
-                                         boost::forward_traversal_tag
-                                         >
-    {
-
-    public:
-        typedef typename boost::tuple<unsigned, T, T> value_type;
-        typedef vertex_vector<T> container_type;
-
-        vertex_iterator()
-            : v_(SEG_END,0,0),
-              vertices_(),
-              pos_(0)
-        {}
-
-        explicit vertex_iterator(container_type const& vertices)
-            : vertices_(&vertices),
-              pos_(0)
-        {
-            increment();
-        }
-
-    private:
-        friend class boost::iterator_core_access;
-
-        void increment()
-        {
-            boost::get<0>(v_) = vertices_->get_vertex(pos_++, &boost::get<1>(v_), &boost::get<2>(v_));
-        }
-
-        bool equal( vertex_iterator const& other) const
-        {
-            return boost::get<0>(v_) == boost::get<0>(other.v_);
-        }
-
-        value_type const& dereference() const
-        {
-            return v_;
-        }
-
-        value_type v_;
-        container_type const *vertices_;
-        unsigned pos_;
-    };
-
-    }}
-
-
-#endif // MAPNIK_VERTEX_ITERATOR_HPP
diff --git a/plugins/input/raster/raster_featureset.cpp b/plugins/input/raster/raster_featureset.cpp
index affe873be..9d7c0b4d1 100644
--- a/plugins/input/raster/raster_featureset.cpp
+++ b/plugins/input/raster/raster_featureset.cpp
@@ -113,7 +113,7 @@ feature_ptr raster_featureset<LookupPolicy>::next()
 
                         image_data_32 image(width,height);
                         reader->read(x_off, y_off, image);
-                        feature->set_raster(boost::make_shared<raster>(intersect, image));
+                        feature->set_raster(boost::make_shared<raster>(intersect, image,reader->premultiplied_alpha()));
                     }
                 }
             }
diff --git a/plugins/input/sqlite/sqlite_datasource.cpp b/plugins/input/sqlite/sqlite_datasource.cpp
index 1b769af53..f662efb2f 100644
--- a/plugins/input/sqlite/sqlite_datasource.cpp
+++ b/plugins/input/sqlite/sqlite_datasource.cpp
@@ -524,7 +524,7 @@ boost::optional<mapnik::datasource::geometry_t> sqlite_datasource::get_geometry_
             if (data)
             {
                 boost::ptr_vector<mapnik::geometry_type> paths;
-                if (mapnik::geometry_utils::from_wkb(paths, data, size, mapnik::wkbAuto))
+                if (mapnik::geometry_utils::from_wkb(paths, data, size, format_))
                 {
                     mapnik::util::to_ds_type(paths,result);
                     if (result)
diff --git a/src/agg/process_raster_symbolizer.cpp b/src/agg/process_raster_symbolizer.cpp
index 2830b2564..d8f145a7d 100644
--- a/src/agg/process_raster_symbolizer.cpp
+++ b/src/agg/process_raster_symbolizer.cpp
@@ -96,7 +96,9 @@ void agg_renderer<T>::process(raster_symbolizer const& sym,
                                                    filter_radius);
                 }
             }
-            composite(current_buffer_->data(), target.data_, sym.comp_op(), sym.get_opacity(), start_x, start_y, true);
+            composite(current_buffer_->data(), target.data_,
+                      sym.comp_op(), sym.get_opacity(),
+                      start_x, start_y, !source->premultiplied_alpha_);
         }
     }
 }
diff --git a/src/jpeg_reader.cpp b/src/jpeg_reader.cpp
index c98dddb49..df03314f9 100644
--- a/src/jpeg_reader.cpp
+++ b/src/jpeg_reader.cpp
@@ -50,6 +50,7 @@ public:
     ~JpegReader();
     unsigned width() const;
     unsigned height() const;
+    inline bool premultiplied_alpha() const { return true ;}
     void read(unsigned x,unsigned y,image_data_32& image);
 private:
     void init();
diff --git a/src/png_reader.cpp b/src/png_reader.cpp
index 0cde465f5..dde14ed70 100644
--- a/src/png_reader.cpp
+++ b/src/png_reader.cpp
@@ -46,6 +46,7 @@ public:
     ~png_reader();
     unsigned width() const;
     unsigned height() const;
+    bool premultiplied_alpha() const { return false; } //http://www.libpng.org/pub/png/spec/1.1/PNG-Rationale.html
     void read(unsigned x,unsigned y,image_data_32& image);
 private:
     void init();
diff --git a/src/tiff_reader.cpp b/src/tiff_reader.cpp
index effb6551b..8cf5f89ae 100644
--- a/src/tiff_reader.cpp
+++ b/src/tiff_reader.cpp
@@ -64,7 +64,7 @@ private:
     int tile_width_;
     int tile_height_;
     tiff_ptr tif_;
-
+    bool premultiplied_alpha_;
 public:
     enum TiffType {
         generic=1,
@@ -75,6 +75,7 @@ public:
     virtual ~tiff_reader();
     unsigned width() const;
     unsigned height() const;
+    bool premultiplied_alpha() const;
     void read(unsigned x,unsigned y,image_data_32& image);
 private:
     tiff_reader(const tiff_reader&);
@@ -103,7 +104,8 @@ tiff_reader::tiff_reader(std::string const& file_name)
       height_(0),
       rows_per_strip_(0),
       tile_width_(0),
-      tile_height_(0)
+      tile_height_(0),
+      premultiplied_alpha_(false)
 {
     init();
 }
@@ -132,6 +134,16 @@ void tiff_reader::init()
         {
             read_method_=stripped;
         }
+        //TIFFTAG_EXTRASAMPLES
+        uint16 extrasamples;
+        uint16* sampleinfo;
+        TIFFGetFieldDefaulted(tif, TIFFTAG_EXTRASAMPLES,
+                              &extrasamples, &sampleinfo);
+        if (extrasamples == 1 &&
+            sampleinfo[0] == EXTRASAMPLE_ASSOCALPHA)
+        {
+            premultiplied_alpha_ = true;
+        }
     }
     else
     {
@@ -156,6 +168,10 @@ unsigned tiff_reader::height() const
     return height_;
 }
 
+bool tiff_reader::premultiplied_alpha() const
+{
+    return premultiplied_alpha_;
+}
 
 void tiff_reader::read(unsigned x,unsigned y,image_data_32& image)
 {
diff --git a/src/wkt/wkt_generator.cpp b/src/wkt/wkt_generator.cpp
index f9d82efb6..9e04640b1 100644
--- a/src/wkt/wkt_generator.cpp
+++ b/src/wkt/wkt_generator.cpp
@@ -24,19 +24,22 @@
 
 #if BOOST_VERSION >= 104700
 
+#include <mapnik/geometry.hpp>
 #include <mapnik/util/geometry_wkt_generator.hpp>
-#include <mapnik/util/vertex_iterator.hpp>
+#include <mapnik/util/path_iterator.hpp>
 #include <mapnik/util/container_adapter.hpp>
 
 namespace mapnik { namespace util {
 
-boost::tuple<unsigned,bool> detail::multi_geometry_type::operator() (geometry_container const& geom) const
+template <typename T>
+boost::tuple<unsigned,bool> detail::multi_geometry_type<T>::operator() (T const& geom) const
 {
+    typedef T geometry_container;
     unsigned type = 0u;
     bool collection = false;
 
-    geometry_container::const_iterator itr = geom.begin();
-    geometry_container::const_iterator end = geom.end();
+    typename geometry_container::const_iterator itr = geom.begin();
+    typename geometry_container::const_iterator end = geom.end();
 
     for ( ; itr != end; ++itr)
     {
@@ -50,8 +53,8 @@ boost::tuple<unsigned,bool> detail::multi_geometry_type::operator() (geometry_co
     return boost::tuple<unsigned,bool>(type, collection);
 }
 
-template <typename OutputIterator>
-wkt_generator<OutputIterator>::wkt_generator(bool single)
+template <typename OutputIterator, typename Geometry>
+wkt_generator<OutputIterator, Geometry>::wkt_generator(bool single)
     : wkt_generator::base_type(wkt)
 {
     using boost::spirit::karma::uint_;
@@ -62,50 +65,50 @@ wkt_generator<OutputIterator>::wkt_generator(bool single)
     using boost::spirit::karma::_r1;
     using boost::spirit::karma::eps;
     using boost::spirit::karma::string;
-    
+
     wkt = point | linestring | polygon
         ;
-    
+
     point = &uint_(mapnik::Point)[_1 = _type(_val)]
         << string[ phoenix::if_ (single) [_1 = "Point("]
                    .else_[_1 = "("]]
         << point_coord [_1 = _first(_val)] << lit(')')
         ;
-    
+
     linestring = &uint_(mapnik::LineString)[_1 = _type(_val)]
         << string[ phoenix::if_ (single) [_1 = "LineString("]
                    .else_[_1 = "("]]
         << coords
         << lit(')')
         ;
-    
+
     polygon = &uint_(mapnik::Polygon)[_1 = _type(_val)]
         << string[ phoenix::if_ (single) [_1 = "Polygon("]
                    .else_[_1 = "("]]
         << coords2
         << lit("))")
         ;
-    
-    point_coord = &uint_ << coord_type << lit(' ') << coord_type
+
+    point_coord = &uint_ << coordinate << lit(' ') << coordinate
         ;
-    
+
     polygon_coord %= ( &uint_(mapnik::SEG_MOVETO) << eps[_r1 += 1]
                        << string[ if_ (_r1 > 1) [_1 = "),("]
                                   .else_[_1 = "("] ] | &uint_ << ",")
-        << coord_type
+        << coordinate
         << lit(' ')
-        << coord_type
+        << coordinate
         ;
-    
+
     coords2 %= *polygon_coord(_a)
         ;
-    
+
     coords = point_coord % lit(',')
         ;
 }
 
-template <typename OutputIterator>
-wkt_multi_generator<OutputIterator>::wkt_multi_generator()
+template <typename OutputIterator, typename GeometryContainer>
+wkt_multi_generator<OutputIterator, GeometryContainer>::wkt_multi_generator()
     : wkt_multi_generator::base_type(wkt)
 {
     using boost::spirit::karma::lit;
@@ -138,10 +141,10 @@ wkt_multi_generator<OutputIterator>::wkt_multi_generator()
 
 }
 
-template struct mapnik::util::wkt_generator<std::back_insert_iterator<std::string> >;
-template struct mapnik::util::wkt_multi_generator<std::back_insert_iterator<std::string> >;
+template struct mapnik::util::wkt_generator<std::back_insert_iterator<std::string>, mapnik::geometry_type>;
+template struct mapnik::util::wkt_multi_generator<std::back_insert_iterator<std::string>, mapnik::geometry_container >;
 
 
 }}
 
-#endif
\ No newline at end of file
+#endif
diff --git a/tests/data/raster/river.tiff b/tests/data/raster/river.tiff
new file mode 100644
index 000000000..1f68f396d
Binary files /dev/null and b/tests/data/raster/river.tiff differ
diff --git a/tests/data/raster/river_merc.tiff b/tests/data/raster/river_merc.tiff
new file mode 100644
index 000000000..447263f4b
Binary files /dev/null and b/tests/data/raster/river_merc.tiff differ
diff --git a/tests/data/raster/river_wgs.tiff b/tests/data/raster/river_wgs.tiff
new file mode 100644
index 000000000..60fe5577f
Binary files /dev/null and b/tests/data/raster/river_wgs.tiff differ
diff --git a/tests/data/raster/white-alpha-assoc-alpha-correct.tiff b/tests/data/raster/white-alpha-assoc-alpha-correct.tiff
new file mode 100644
index 000000000..2085393c4
Binary files /dev/null and b/tests/data/raster/white-alpha-assoc-alpha-correct.tiff differ
diff --git a/tests/data/raster/white-alpha.tiff b/tests/data/raster/white-alpha-assoc-alpha-wrong.tiff
similarity index 100%
rename from tests/data/raster/white-alpha.tiff
rename to tests/data/raster/white-alpha-assoc-alpha-wrong.tiff
diff --git a/tests/python_tests/multi_tile_raster_test.py b/tests/python_tests/multi_tile_raster_test.py
index ce2854f31..fff685487 100644
--- a/tests/python_tests/multi_tile_raster_test.py
+++ b/tests/python_tests/multi_tile_raster_test.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 from nose.tools import *
-from utilities import execution_path, save_data, contains_word
+from utilities import execution_path, contains_word
 
 import os, mapnik
 
@@ -40,8 +40,6 @@ def test_multi_tile_policy():
         im = mapnik.Image(_map.width, _map.height)
         mapnik.render(_map, im)
 
-        save_data('test_multi_tile_policy.png', im.tostring('png'))
-
         # test green chunk
         eq_(im.view(0,64,1,1).tostring(), '\x00\xff\x00\xff')
         eq_(im.view(127,64,1,1).tostring(), '\x00\xff\x00\xff')
diff --git a/tests/python_tests/raster_symbolizer_test.py b/tests/python_tests/raster_symbolizer_test.py
index f285c615f..9e7870703 100644
--- a/tests/python_tests/raster_symbolizer_test.py
+++ b/tests/python_tests/raster_symbolizer_test.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 from nose.tools import *
-from utilities import execution_path, save_data, contains_word
+from utilities import execution_path, contains_word
 
 import os, mapnik
 
@@ -51,8 +51,6 @@ def test_dataraster_coloring():
 
         im = mapnik.Image(_map.width,_map.height)
         mapnik.render(_map, im)
-        # save a png somewhere so we can see it
-        save_data('test_dataraster_coloring.png', im.tostring('png'))
         imdata = im.tostring()
         # we have some values in the [20,30) interval so check that they're colored
         assert contains_word('\xff\xff\x00\xff', imdata)
@@ -135,8 +133,6 @@ def test_raster_with_alpha_blends_correctly_with_background():
         mim = mapnik.Image(WIDTH, HEIGHT)
 
         mapnik.render(map, mim)
-        save_data('test_raster_with_alpha_blends_correctly_with_background.png',
-                  mim.tostring('png'))
         imdata = mim.tostring()
         # All white is expected
         assert contains_word('\xff\xff\xff\xff', imdata)
@@ -166,8 +162,6 @@ def test_raster_warping():
 
         im = mapnik.Image(_map.width,_map.height)
         mapnik.render(_map, im)
-        # save a png somewhere so we can see it
-        save_data('test_raster_warping.png', im.tostring('png'))
         imdata = im.tostring()
         assert contains_word('\xff\xff\x00\xff', imdata)
 
@@ -195,9 +189,6 @@ def test_raster_warping_does_not_overclip_source():
 
         im = mapnik.Image(_map.width,_map.height)
         mapnik.render(_map, im)
-        # save a png somewhere so we can see it
-        save_data('test_raster_warping_does_not_overclip_source.png',
-                  im.tostring('png'))
         assert im.view(0,200,1,1).tostring()=='\xff\xff\x00\xff'
 
 if __name__ == "__main__":
diff --git a/tests/python_tests/utilities.py b/tests/python_tests/utilities.py
index f76c5e54a..b47df7be4 100644
--- a/tests/python_tests/utilities.py
+++ b/tests/python_tests/utilities.py
@@ -15,20 +15,6 @@ class TodoPlugin(ErrorClassPlugin):
 
     todo = ErrorClass(Todo, label='TODO', isfailure=False)
 
-def save_data(filename, data, key='MAPNIK_TEST_DATA_DIR'):
-    """Saves bytestring 'data' into os.environ[key]/filename if
-    key in os.environ"""
-    if key in os.environ:
-        dir = os.environ[key]
-        if not os.path.exists(dir):
-            os.makedirs(dir)
-        fname = os.path.join(dir, filename)
-        f = open(fname, 'w')
-        try:
-            f.write(data)
-        finally:
-            f.close()
-
 def contains_word(word, bytestring_):
     """
     Checks that a bytestring contains a given word. len(bytestring) should be
diff --git a/tests/visual_tests/compare.py b/tests/visual_tests/compare.py
index 43bd251d9..d2f05b08d 100644
--- a/tests/visual_tests/compare.py
+++ b/tests/visual_tests/compare.py
@@ -24,6 +24,10 @@ def compare_pixels(pixel1, pixel2):
     else:
         return False
 
+def fail(actual,expected,message):
+    global errors
+    errors.append((message, actual, expected))
+
 # compare two images and return number of different pixels
 def compare(actual, expected):
     global errors
@@ -52,11 +56,14 @@ def compare(actual, expected):
 def summary(generate=False):
     global errors
     global passed
-    print "-"*80
-    print "Visual text rendering summary:",
+    
     if len(errors) != 0:
-        for error in errors:
-            if (error[0] is None):
+        msg = "Visual text rendering: %s failures" % len(errors)
+        print "-"*len(msg)
+        print msg
+        print "-"*len(msg)
+        for idx,error in enumerate(errors):
+            if error[0] is None:
                 if generate:
                     actual = open(error[1],'r').read()
                     open(error[2],'wb').write(actual)
@@ -64,9 +71,14 @@ def summary(generate=False):
                     continue
                 else:
                     print "Could not verify %s: No reference image found!" % error[1]
-            else:
-                print "Failed: %d different pixels:\n\t%s (actual)\n\t%s (expected)" % error
+            elif isinstance(error[0],int):
+                print str(idx+1) + ") \x1b[34m%s different pixels\x1b[0m:\n\t%s (\x1b[31mactual\x1b[0m)\n\t%s (\x1b[32mexpected\x1b[0m)" % error
+            elif isinstance(error[0],str):
+                print str(idx+1) + ") \x1b[31mfailure to run test:\x1b[0m %s" % error[0]
         sys.exit(1)
     else:
-        print 'All %s tests passed: \x1b[1;32m✓ \x1b[0m' % passed
+        msg = 'All %s visual tests passed: \x1b[1;32m✓ \x1b[0m' % passed
+        print "-"*len(msg)
+        print msg
+        print "-"*len(msg)
         sys.exit(0)
diff --git a/tests/visual_tests/images/tiff-alpha-broken-assoc-alpha-gdal-600-reference.png b/tests/visual_tests/images/tiff-alpha-broken-assoc-alpha-gdal-600-reference.png
new file mode 100644
index 000000000..3c79bb304
Binary files /dev/null and b/tests/visual_tests/images/tiff-alpha-broken-assoc-alpha-gdal-600-reference.png differ
diff --git a/tests/visual_tests/images/tiff-alpha-broken-assoc-alpha-raster-600-reference.png b/tests/visual_tests/images/tiff-alpha-broken-assoc-alpha-raster-600-reference.png
new file mode 100644
index 000000000..3c79bb304
Binary files /dev/null and b/tests/visual_tests/images/tiff-alpha-broken-assoc-alpha-raster-600-reference.png differ
diff --git a/tests/visual_tests/images/tiff-alpha-gdal-600-reference.png b/tests/visual_tests/images/tiff-alpha-gdal-600-reference.png
index 3c79bb304..0bb7ff1cf 100644
Binary files a/tests/visual_tests/images/tiff-alpha-gdal-600-reference.png and b/tests/visual_tests/images/tiff-alpha-gdal-600-reference.png differ
diff --git a/tests/visual_tests/images/tiff-alpha-raster-600-reference.png b/tests/visual_tests/images/tiff-alpha-raster-600-reference.png
index 3c79bb304..0bb7ff1cf 100644
Binary files a/tests/visual_tests/images/tiff-alpha-raster-600-reference.png and b/tests/visual_tests/images/tiff-alpha-raster-600-reference.png differ
diff --git a/tests/visual_tests/images/tiff-opaque-edge-gdal-256-reference.png b/tests/visual_tests/images/tiff-opaque-edge-gdal-256-reference.png
new file mode 100644
index 000000000..cb90dea1d
Binary files /dev/null and b/tests/visual_tests/images/tiff-opaque-edge-gdal-256-reference.png differ
diff --git a/tests/visual_tests/images/tiff-opaque-edge-raster-256-reference.png b/tests/visual_tests/images/tiff-opaque-edge-raster-256-reference.png
new file mode 100644
index 000000000..cb90dea1d
Binary files /dev/null and b/tests/visual_tests/images/tiff-opaque-edge-raster-256-reference.png differ
diff --git a/tests/visual_tests/styles/tiff-alpha-broken-assoc-alpha-gdal.xml b/tests/visual_tests/styles/tiff-alpha-broken-assoc-alpha-gdal.xml
new file mode 100644
index 000000000..358a2260b
--- /dev/null
+++ b/tests/visual_tests/styles/tiff-alpha-broken-assoc-alpha-gdal.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE Map[]>
+<Map srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over" background-color="red">
+
+<Style name="white">
+  <Rule>
+    <RasterSymbolizer opacity="1" scaling="bilinear" comp-op="src-over"/>
+  </Rule>
+</Style>
+<Layer name="white"
+  srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over">
+    <StyleName>white</StyleName>
+    <Datasource>
+       <!-- tiffinfo data/raster/white-alpha-assoc-alpha-wrong.tiff reports 'Extra Samples: 1<assoc-alpha>' which is incorrect --> 
+       <!-- https://github.com/mapnik/mapnik/issues/1511 --> 
+       <Parameter name="file">../../data/raster/white-alpha-assoc-alpha-wrong.tiff</Parameter>
+       <Parameter name="type">gdal</Parameter>
+    </Datasource>
+  </Layer>
+
+</Map>
\ No newline at end of file
diff --git a/tests/visual_tests/styles/tiff-alpha-broken-assoc-alpha-raster.xml b/tests/visual_tests/styles/tiff-alpha-broken-assoc-alpha-raster.xml
new file mode 100644
index 000000000..61cdb9c47
--- /dev/null
+++ b/tests/visual_tests/styles/tiff-alpha-broken-assoc-alpha-raster.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE Map[]>
+<Map srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over" background-color="red">
+
+<Style name="white">
+  <Rule>
+    <RasterSymbolizer opacity="1" scaling="bilinear" comp-op="src-over"/>
+  </Rule>
+</Style>
+<Layer name="white"
+  srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over">
+    <StyleName>white</StyleName>
+    <Datasource>
+       <!-- tiffinfo data/raster/white-alpha-assoc-alpha-wrong.tiff reports 'Extra Samples: 1<assoc-alpha>' which is incorrect --> 
+       <!-- https://github.com/mapnik/mapnik/issues/1511 --> 
+       <Parameter name="file">../../data/raster/white-alpha-assoc-alpha-wrong.tiff</Parameter>
+       <Parameter name="type">raster</Parameter>
+       <Parameter name="extent">1001859.9561,5922814.94334,1021141.75555,5942096.74279</Parameter>
+    </Datasource>
+  </Layer>
+
+</Map>
\ No newline at end of file
diff --git a/tests/visual_tests/styles/tiff-alpha-gdal.xml b/tests/visual_tests/styles/tiff-alpha-gdal.xml
index e7fe88453..ce42b1a3f 100644
--- a/tests/visual_tests/styles/tiff-alpha-gdal.xml
+++ b/tests/visual_tests/styles/tiff-alpha-gdal.xml
@@ -11,7 +11,7 @@
   srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over">
     <StyleName>white</StyleName>
     <Datasource>
-       <Parameter name="file">../../data/raster/white-alpha.tiff</Parameter>
+       <Parameter name="file">../../data/raster/white-alpha-assoc-alpha-correct.tiff</Parameter>
        <Parameter name="type">gdal</Parameter>
     </Datasource>
   </Layer>
diff --git a/tests/visual_tests/styles/tiff-alpha-raster.xml b/tests/visual_tests/styles/tiff-alpha-raster.xml
index ce9e2fb6c..a86c7603d 100644
--- a/tests/visual_tests/styles/tiff-alpha-raster.xml
+++ b/tests/visual_tests/styles/tiff-alpha-raster.xml
@@ -11,7 +11,7 @@
   srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over">
     <StyleName>white</StyleName>
     <Datasource>
-       <Parameter name="file">../../data/raster/white-alpha.tiff</Parameter>
+       <Parameter name="file">../../data/raster/white-alpha-assoc-alpha-correct.tiff</Parameter>
        <Parameter name="type">raster</Parameter>
        <Parameter name="extent">1001859.9561,5922814.94334,1021141.75555,5942096.74279</Parameter>
     </Datasource>
diff --git a/tests/visual_tests/styles/tiff-opaque-edge-gdal.xml b/tests/visual_tests/styles/tiff-opaque-edge-gdal.xml
new file mode 100644
index 000000000..5d62e2d8b
--- /dev/null
+++ b/tests/visual_tests/styles/tiff-opaque-edge-gdal.xml
@@ -0,0 +1,17 @@
+<Map srs="+init=EPSG:4326" background-color="white">
+
+<Style name="test">
+  <Rule>
+    <RasterSymbolizer scaling="bilinear" />
+  </Rule>
+</Style>
+
+<Layer name="test" srs="+init=EPSG:4326">
+    <StyleName>test</StyleName>
+    <Datasource>
+        <Parameter name="file">../../data/raster/river.tiff</Parameter>
+        <Parameter name="type">gdal</Parameter>
+    </Datasource>
+</Layer>
+
+</Map>
\ No newline at end of file
diff --git a/tests/visual_tests/styles/tiff-opaque-edge-raster.xml b/tests/visual_tests/styles/tiff-opaque-edge-raster.xml
new file mode 100644
index 000000000..ec5519725
--- /dev/null
+++ b/tests/visual_tests/styles/tiff-opaque-edge-raster.xml
@@ -0,0 +1,18 @@
+<Map srs="+init=EPSG:4326" background-color="white">
+
+<Style name="test">
+  <Rule>
+    <RasterSymbolizer scaling="bilinear" />
+  </Rule>
+</Style>
+
+<Layer name="test" srs="+init=EPSG:4326">
+    <StyleName>test</StyleName>
+    <Datasource>
+        <Parameter name="file">../../data/raster/river.tiff</Parameter>
+        <Parameter name="type">raster</Parameter>
+        <Parameter name="extent">0,0,256,210</Parameter>
+    </Datasource>
+</Layer>
+
+</Map>
\ No newline at end of file
diff --git a/tests/visual_tests/test.py b/tests/visual_tests/test.py
index 34007ced2..12938df55 100755
--- a/tests/visual_tests/test.py
+++ b/tests/visual_tests/test.py
@@ -2,9 +2,11 @@
 # -*- coding: utf-8 -*-
 
 import mapnik
+mapnik.logger.set_severity(mapnik.severity_type.None)
+
 import sys
 import os.path
-from compare import compare, summary
+from compare import compare, summary, fail
 
 defaults = {
     'sizes': [(500, 100)]
@@ -51,12 +53,16 @@ files = [
     {'name': "line-offset", 'sizes':[(900, 250)],'bbox': mapnik.Box2d(-5.192, 50.189, -5.174, 50.195)},
     {'name': "tiff-alpha-gdal", 'sizes':[(600,400)]},
     {'name': "tiff-alpha-raster", 'sizes':[(600,400)]},
+    {'name': "tiff-alpha-broken-assoc-alpha-gdal", 'sizes':[(600,400)]},
+    {'name': "tiff-alpha-broken-assoc-alpha-raster", 'sizes':[(600,400)]},
     {'name': "tiff-alpha-gradient-gdal", 'sizes':[(600,400)]},
     {'name': "tiff-nodata-edge-gdal", 'sizes':[(600,400)]},
     {'name': "tiff-nodata-edge-raster", 'sizes':[(600,400)]},
+    {'name': "tiff-opaque-edge-gdal", 'sizes':[(256,256)]},
+    {'name': "tiff-opaque-edge-raster", 'sizes':[(256,256)]},
     {'name': "shieldsymbolizer-2"},
     {'name': "shieldsymbolizer-3"},
-    {'name': "shieldsymbolizer-4"},
+    {'name': "shieldsymbolizer-4"},    
     {'name': "orientation", 'sizes': [(800, 200)]},
     {'name': "hb-fontsets", 'sizes': [(800, 200)]},
     {'name': "charspacing", 'sizes': [(200, 400)]},
@@ -65,25 +71,28 @@ files = [
 
 def render(filename, width, height, bbox, quiet=False):
     if not quiet:
-        print "Rendering style \"%s\" with size %dx%d ... \x1b[1;32m✓ \x1b[0m" % (filename, width, height)
-        print "-"*80
+        print "\"%s\" with size %dx%d ..." % (filename, width, height),
     m = mapnik.Map(width, height)
-    mapnik.load_map(m, os.path.join(dirname, "styles", "%s.xml" % filename), False)
-    if bbox is not None:
-        m.zoom_to_box(bbox)
-    else:
-        m.zoom_all()
     expected = os.path.join(dirname, "images", '%s-%d-reference.png' % (filename, width))
-    if not os.path.exists('/tmp/mapnik-visual-images'):
-        os.makedirs('/tmp/mapnik-visual-images')
     actual = os.path.join("/tmp/mapnik-visual-images", '%s-%d-agg.png' % (filename, width))
-    mapnik.render_to_file(m, actual)
-    diff = compare(actual, expected)
-    if diff > 0:
-        print "-"*80
-        print '\x1b[33mError:\x1b[0m %u different pixels' % diff
-        print "-"*80
-
+    try:
+        mapnik.load_map(m, os.path.join(dirname, "styles", "%s.xml" % filename), False)
+        if bbox is not None:
+            m.zoom_to_box(bbox)
+        else:
+            m.zoom_all()
+        if not os.path.exists('/tmp/mapnik-visual-images'):
+            os.makedirs('/tmp/mapnik-visual-images')
+        mapnik.render_to_file(m, actual)
+        diff = compare(actual, expected)
+        if not quiet:
+            if diff > 0:
+                print '\x1b[31m✘\x1b[0m (\x1b[34m%u different pixels\x1b[0m)' % diff
+            else:
+                print '\x1b[32m✓\x1b[0m'
+    except Exception, e:
+        sys.stderr.write(e.message + '\n')
+        fail(actual,expected,str(e.message))
     return m
 
 if __name__ == "__main__":