diff --git a/include/mapnik/grid/grid.hpp b/include/mapnik/grid/grid.hpp
index 165b5ef39..298513f2c 100644
--- a/include/mapnik/grid/grid.hpp
+++ b/include/mapnik/grid/grid.hpp
@@ -252,7 +252,15 @@ public:
 
                 for (int x = box.minx(); x < box.maxx(); ++x)
                 {
-                    if (row_from[x-x0] & 0xff000000)
+                    unsigned rgba = row_from[x-x0];
+#ifdef MAPNIK_BIG_ENDIAN
+                    unsigned a = rgba & 0xff;
+#else
+                    unsigned a = (rgba >> 24) & 0xff;
+#endif                    
+                    // if the pixel is more than a tenth
+                    // opaque then burn in the feature id
+                    if (a >= 25)
                     {
                         row_to[x] = id;
                     }
diff --git a/src/grid/grid_renderer.cpp b/src/grid/grid_renderer.cpp
index 1c26dc548..98973b91e 100644
--- a/src/grid/grid_renderer.cpp
+++ b/src/grid/grid_renderer.cpp
@@ -153,7 +153,19 @@ void grid_renderer<T>::render_marker(Feature const& feature, unsigned int step,
     }
     else
     {
-        pixmap_.set_rectangle(feature.id(), **marker.get_bitmap_data(), x, y);
+        image_data_32 const& data = **marker.get_bitmap_data();
+        if (step == 1 && scale_factor_ == 1.0)
+        {
+            pixmap_.set_rectangle(feature.id(), data, x, y);    
+        }
+        else
+        {
+            double ratio = (1.0/step);
+            image_data_32 target(ratio * data.width(), ratio * data.height());
+            mapnik::scale_image_agg<image_data_32>(target,data, SCALING_NEAR,
+                scale_factor_, 0.0, 0.0, 1.0, ratio);
+            pixmap_.set_rectangle(feature.id(), target, x, y);
+        }
     }
     pixmap_.add_feature(feature);
 }
diff --git a/src/grid/process_point_symbolizer.cpp b/src/grid/process_point_symbolizer.cpp
index 3b7e0570c..8daac7136 100644
--- a/src/grid/process_point_symbolizer.cpp
+++ b/src/grid/process_point_symbolizer.cpp
@@ -68,8 +68,8 @@ void grid_renderer<T>::process(point_symbolizer const& sym,
             prj_trans.backward(x,y,z);
             t_.forward(&x,&y);
 
-            int w = (*marker)->width();
-            int h = (*marker)->height();
+            int w = (*marker)->width() * (1.0/pixmap_.get_step());
+            int h = (*marker)->height() * (1.0/pixmap_.get_step());
 
             int px = int(floor(x - 0.5 * w));
             int py = int(floor(y - 0.5 * h));