diff --git a/include/mapnik/feature_style_processor.hpp b/include/mapnik/feature_style_processor.hpp
index 476197a58..da644007f 100644
--- a/include/mapnik/feature_style_processor.hpp
+++ b/include/mapnik/feature_style_processor.hpp
@@ -110,28 +110,31 @@ namespace mapnik
             if (ds)
             {
                Envelope<double> const& ext=m_.getCurrentExtent();
+               Envelope<double> bbox(ext);
                projection proj1(lay.srs());
                proj_transform prj_trans(proj0,proj1);
-
-               Envelope<double> layer_ext = lay.envelope();
-               double lx0 = layer_ext.minx();
-               double ly0 = layer_ext.miny();
-               double lz0 = 0.0;
-               double lx1 = layer_ext.maxx();
-               double ly1 = layer_ext.maxy();
-               double lz1 = 0.0;
-               // back project layers extent into main map projection
-               prj_trans.backward(lx0,ly0,lz0);
-               prj_trans.backward(lx1,ly1,lz1);
-               // clip query bbox
-               lx0 = std::max(ext.minx(),lx0);
-               ly0 = std::max(ext.miny(),ly0);
-               lx1 = std::min(ext.maxx(),lx1);
-               ly1 = std::min(ext.maxy(),ly1);
                
-               prj_trans.forward(lx0,ly0,lz0);
-               prj_trans.forward(lx1,ly1,lz1);
-               Envelope<double> bbox(lx0,ly0,lx1,ly1);
+               if (proj0 != proj1) {
+                  Envelope<double> layer_ext = lay.envelope();
+                  double lx0 = layer_ext.minx();
+                  double ly0 = layer_ext.miny();
+                  double lz0 = 0.0;
+                  double lx1 = layer_ext.maxx();
+                  double ly1 = layer_ext.maxy();
+                  double lz1 = 0.0;
+                  // back project layers extent into main map projection
+                  prj_trans.backward(lx0,ly0,lz0);
+                  prj_trans.backward(lx1,ly1,lz1);
+                  // clip query bbox
+                  lx0 = std::max(ext.minx(),lx0);
+                  ly0 = std::max(ext.miny(),ly0);
+                  lx1 = std::min(ext.maxx(),lx1);
+                  ly1 = std::min(ext.maxy(),ly1);
+
+                  prj_trans.forward(lx0,ly0,lz0);
+                  prj_trans.forward(lx1,ly1,lz1);
+                  bbox = Envelope<double>(lx0,ly0,lx1,ly1);
+               }
                double resolution = m_.getWidth()/bbox.width();
                query q(bbox,resolution); //BBOX query
                
diff --git a/include/mapnik/projection.hpp b/include/mapnik/projection.hpp
index ac26b8872..76a78163b 100644
--- a/include/mapnik/projection.hpp
+++ b/include/mapnik/projection.hpp
@@ -57,6 +57,8 @@ namespace mapnik {
         ~projection();
         
         projection& operator=(projection const& rhs);
+        bool operator==(const projection& other) const;
+        bool operator!=(const projection& other) const;
         bool is_initialized() const;
         bool is_geographic() const;
         std::string const& params() const;
diff --git a/src/projection.cpp b/src/projection.cpp
index 511b2d673..9143b59f0 100644
--- a/src/projection.cpp
+++ b/src/projection.cpp
@@ -52,7 +52,17 @@ namespace mapnik {
         swap(tmp);
         return *this;
     }
-        
+    
+    bool projection::operator==(const projection& other) const 
+    {
+        return (params_ == other.params_);
+    }
+    
+    bool projection::operator!=(const projection& other) const 
+    {
+        return !(*this == other);
+    }
+    
     bool projection::is_initialized() const
     {
         return proj_ ? true : false;