diff --git a/include/mapnik/params.hpp b/include/mapnik/params.hpp
index a38fa54e7..535cacb38 100644
--- a/include/mapnik/params.hpp
+++ b/include/mapnik/params.hpp
@@ -51,6 +51,10 @@ struct value_holder : value_holder_base
     value_holder()
         : value_holder_base() {}
 
+    // C-string -> std::string
+    value_holder(char const* str)
+        : value_holder(std::string(str)) {}
+
     // perfect forwarding
     template <typename T>
     value_holder(T && obj)
diff --git a/include/mapnik/symbolizer_base.hpp b/include/mapnik/symbolizer_base.hpp
index fc88c579c..f07cf3d2a 100644
--- a/include/mapnik/symbolizer_base.hpp
+++ b/include/mapnik/symbolizer_base.hpp
@@ -101,7 +101,7 @@ struct strict_value : value_base_type
     strict_value() = default;
 
     strict_value(const char* val)
-        : value_base_type(val) {}
+        : value_base_type(std::string(val)) {}
 
     template <typename T>
     strict_value(T const& obj)
diff --git a/include/mapnik/xml_attribute_cast.hpp b/include/mapnik/xml_attribute_cast.hpp
index fb3b7ebdc..cafa7e79a 100644
--- a/include/mapnik/xml_attribute_cast.hpp
+++ b/include/mapnik/xml_attribute_cast.hpp
@@ -55,7 +55,7 @@ struct do_xml_attribute_cast
 {
     static inline boost::optional<T> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& /*source*/)
     {
-        std::string err_msg("No conversion from std::string to");
+        std::string err_msg("No conversion from std::string to ");
         err_msg += std::string(typeid(T).name());
         throw std::runtime_error(err_msg);
     }
@@ -74,6 +74,19 @@ struct do_xml_attribute_cast<mapnik::boolean_type>
     }
 };
 
+// specialization for mapnik::value_bool
+template <>
+struct do_xml_attribute_cast<mapnik::value_bool>
+{
+    static inline boost::optional<mapnik::value_bool> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& source)
+    {
+        bool result;
+        if (mapnik::util::string2bool(source, result))
+            return boost::optional<mapnik::value_bool>(result);
+        return boost::optional<mapnik::value_bool>();
+    }
+};
+
 // specialization for int
 template <>
 struct do_xml_attribute_cast<int>
diff --git a/plugins/input/postgis/postgis_datasource.cpp b/plugins/input/postgis/postgis_datasource.cpp
index 8aef44414..2653e5757 100644
--- a/plugins/input/postgis/postgis_datasource.cpp
+++ b/plugins/input/postgis/postgis_datasource.cpp
@@ -479,7 +479,7 @@ postgis_datasource::postgis_datasource(parameters const& params)
         // Finally, add unique metadata to layer descriptor
         mapnik::parameters & extra_params = desc_.get_extra_parameters();
         // explicitly make copies of values due to https://github.com/mapnik/mapnik/issues/2651
-        extra_params["srid"] = srid_;
+        extra_params["srid"] = mapnik::value_integer(srid_);
         if (!key_field_.empty())
         {
             extra_params["key_field"] = key_field_;
diff --git a/src/load_map.cpp b/src/load_map.cpp
index f21708274..fcb04c003 100644
--- a/src/load_map.cpp
+++ b/src/load_map.cpp
@@ -200,7 +200,7 @@ void map_parser::parse_map(Map & map, xml_node const& node, std::string const& b
             {
                 map.set_background(*bgcolor);
             }
-            
+
             optional<std::string> image_filename = map_node.get_opt_attr<std::string>("background-image");
             if (image_filename)
             {
@@ -891,7 +891,7 @@ void map_parser::parse_symbolizer_base(symbolizer_base &sym, xml_node const& nod
 {
     set_symbolizer_property<symbolizer_base,double>(sym, keys::simplify_tolerance, node);
     set_symbolizer_property<symbolizer_base,double>(sym, keys::smooth, node);
-    set_symbolizer_property<symbolizer_base,boolean_type>(sym, keys::clip, node);
+    set_symbolizer_property<symbolizer_base,value_bool>(sym, keys::clip, node);
     set_symbolizer_property<symbolizer_base,composite_mode_e>(sym, keys::comp_op, node);
     set_symbolizer_property<symbolizer_base,transform_type>(sym, keys::geometry_transform, node);
     set_symbolizer_property<symbolizer_base,simplify_algorithm_e>(sym, keys::simplify_algorithm, node);
@@ -907,8 +907,8 @@ void map_parser::parse_point_symbolizer(rule & rule, xml_node const & node)
         point_symbolizer sym;
         parse_symbolizer_base(sym, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::opacity, node);
-        set_symbolizer_property<symbolizer_base,boolean_type>(sym, keys::allow_overlap, node);
-        set_symbolizer_property<symbolizer_base,boolean_type>(sym, keys::ignore_placement, node);
+        set_symbolizer_property<symbolizer_base,value_bool>(sym, keys::allow_overlap, node);
+        set_symbolizer_property<symbolizer_base,value_bool>(sym, keys::ignore_placement, node);
         set_symbolizer_property<symbolizer_base,point_placement_enum>(sym, keys::point_placement_type, node);
         set_symbolizer_property<symbolizer_base,transform_type>(sym, keys::image_transform, node);
         if (file && !file->empty())
@@ -1011,9 +1011,9 @@ void map_parser::parse_markers_symbolizer(rule & rule, xml_node const& node)
         set_symbolizer_property<symbolizer_base,double>(sym, keys::offset, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::width, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::height, node);
-        set_symbolizer_property<symbolizer_base,boolean_type>(sym, keys::allow_overlap, node);
-        set_symbolizer_property<symbolizer_base,boolean_type>(sym, keys::avoid_edges, node);
-        set_symbolizer_property<symbolizer_base,boolean_type>(sym, keys::ignore_placement, node);
+        set_symbolizer_property<symbolizer_base,value_bool>(sym, keys::allow_overlap, node);
+        set_symbolizer_property<symbolizer_base,value_bool>(sym, keys::avoid_edges, node);
+        set_symbolizer_property<symbolizer_base,value_bool>(sym, keys::ignore_placement, node);
         set_symbolizer_property<symbolizer_base,color>(sym, keys::fill, node);
         set_symbolizer_property<symbolizer_base,transform_type>(sym, keys::image_transform, node);
         set_symbolizer_property<symbolizer_base,marker_placement_enum>(sym, keys::markers_placement_type, node);
@@ -1172,7 +1172,7 @@ void map_parser::parse_shield_symbolizer(rule & rule, xml_node const& node)
         set_symbolizer_property<symbolizer_base,double>(sym, keys::shield_dx, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::shield_dy, node);
         set_symbolizer_property<symbolizer_base,double>(sym, keys::opacity, node);
-        set_symbolizer_property<symbolizer_base,mapnik::boolean_type>(sym, keys::unlock_image, node);
+        set_symbolizer_property<symbolizer_base,value_bool>(sym, keys::unlock_image, node);
 
         std::string file = node.get_attr<std::string>("file");
         if (file.empty())
@@ -1343,7 +1343,7 @@ void map_parser::parse_raster_symbolizer(rule & rule, xml_node const & node)
 
         // premultiplied status of image
         optional<mapnik::boolean_type> premultiplied = node.get_opt_attr<mapnik::boolean_type>("premultiplied");
-        if (premultiplied) put(raster_sym, keys::premultiplied, *premultiplied);
+        if (premultiplied) put(raster_sym, keys::premultiplied, bool(*premultiplied));
 
         bool found_colorizer = false;
         for ( auto const& css : node)
diff --git a/src/text/formatting/layout.cpp b/src/text/formatting/layout.cpp
index ef908c569..9a5ca10aa 100644
--- a/src/text/formatting/layout.cpp
+++ b/src/text/formatting/layout.cpp
@@ -75,9 +75,9 @@ node_ptr layout_node::from_xml(xml_node const& xml, fontset_map const& fontsets)
     if (xml.has_attribute("text-ratio")) set_property_from_xml<double>(n->text_ratio, "text-ratio", xml);
     if (xml.has_attribute("wrap-width")) set_property_from_xml<double>(n->wrap_width, "wrap-width", xml);
     if (xml.has_attribute("wrap-character")) set_property_from_xml<std::string>(n->wrap_char, "wrap-character", xml);
-    if (xml.has_attribute("wrap-before")) set_property_from_xml<mapnik::boolean_type>(n->wrap_before, "wrap-before", xml);
-    if (xml.has_attribute("repeat-wrap-character")) set_property_from_xml<mapnik::boolean_type>(n->repeat_wrap_char, "repeat-wrap-character", xml);
-    if (xml.has_attribute("rotate-displacement")) set_property_from_xml<mapnik::boolean_type>(n->rotate_displacement, "rotate-displacement", xml);
+    if (xml.has_attribute("wrap-before")) set_property_from_xml<mapnik::value_bool>(n->wrap_before, "wrap-before", xml);
+    if (xml.has_attribute("repeat-wrap-character")) set_property_from_xml<mapnik::value_bool>(n->repeat_wrap_char, "repeat-wrap-character", xml);
+    if (xml.has_attribute("rotate-displacement")) set_property_from_xml<mapnik::value_bool>(n->rotate_displacement, "rotate-displacement", xml);
     if (xml.has_attribute("orientation")) set_property_from_xml<double>(n->orientation, "orientation", xml);
     if (xml.has_attribute("horizontal-alignment")) set_property_from_xml<horizontal_alignment_e>(n->halign, "horizontal-alignment", xml);
     if (xml.has_attribute("vertical-alignment")) set_property_from_xml<vertical_alignment_e>(n->valign, "vertical-alignment", xml);
diff --git a/src/text/text_properties.cpp b/src/text/text_properties.cpp
index ef5b9af10..73210d109 100644
--- a/src/text/text_properties.cpp
+++ b/src/text/text_properties.cpp
@@ -103,9 +103,9 @@ void text_symbolizer_properties::text_properties_from_xml(xml_node const& node)
     set_property_from_xml<value_double>(expressions.label_position_tolerance, "label-position-tolerance", node);
     set_property_from_xml<value_double>(expressions.minimum_padding, "minimum-padding", node);
     set_property_from_xml<value_double>(expressions.minimum_path_length, "minimum-path-length", node);
-    set_property_from_xml<boolean_type>(expressions.avoid_edges, "avoid-edges", node);
-    set_property_from_xml<boolean_type>(expressions.allow_overlap, "allow-overlap", node);
-    set_property_from_xml<boolean_type>(expressions.largest_bbox_only, "largest-bbox-only", node);
+    set_property_from_xml<value_bool>(expressions.avoid_edges, "avoid-edges", node);
+    set_property_from_xml<value_bool>(expressions.allow_overlap, "allow-overlap", node);
+    set_property_from_xml<value_bool>(expressions.largest_bbox_only, "largest-bbox-only", node);
     set_property_from_xml<value_double>(expressions.max_char_angle_delta, "max-char-angle-delta", node);
     set_property_from_xml<text_upright_e>(expressions.upright, "upright", node);
 }
@@ -215,9 +215,9 @@ void text_layout_properties::from_xml(xml_node const &node, fontset_map const& f
     set_property_from_xml<double>(text_ratio, "text-ratio", node);
     set_property_from_xml<double>(wrap_width, "wrap-width", node);
     set_property_from_xml<std::string>(wrap_char, "wrap-character", node);
-    set_property_from_xml<boolean_type>(wrap_before, "wrap-before", node);
-    set_property_from_xml<boolean_type>(repeat_wrap_char, "repeat-wrap-character", node);
-    set_property_from_xml<boolean_type>(rotate_displacement, "rotate-displacement", node);
+    set_property_from_xml<value_bool>(wrap_before, "wrap-before", node);
+    set_property_from_xml<value_bool>(repeat_wrap_char, "repeat-wrap-character", node);
+    set_property_from_xml<value_bool>(rotate_displacement, "rotate-displacement", node);
     set_property_from_xml<double>(orientation, "orientation", node);
     set_property_from_xml<vertical_alignment_e>(valign, "vertical-alignment", node);
     set_property_from_xml<horizontal_alignment_e>(halign, "horizontal-alignment", node);
diff --git a/src/xml_tree.cpp b/src/xml_tree.cpp
index b14b8e4e0..2e2a7df8e 100644
--- a/src/xml_tree.cpp
+++ b/src/xml_tree.cpp
@@ -69,6 +69,7 @@ DEFINE_NAME_TRAIT( double, "double")
 DEFINE_NAME_TRAIT( float, "float")
 DEFINE_NAME_TRAIT( unsigned, "unsigned")
 DEFINE_NAME_TRAIT( int, "int")
+DEFINE_NAME_TRAIT( bool, "bool")
 DEFINE_NAME_TRAIT( boolean_type, "boolean_type")
 #ifdef BIGINT
 DEFINE_NAME_TRAIT( mapnik::value_integer, "long long" )
@@ -411,6 +412,7 @@ std::string xml_node::line_to_string() const
 #define compile_get_value(T) template T xml_node::get_value<T>() const
 
 compile_get_opt_attr(boolean_type);
+compile_get_opt_attr(mapnik::value_bool);
 compile_get_opt_attr(std::string);
 compile_get_opt_attr(int);
 compile_get_opt_attr(unsigned);
diff --git a/utils/pgsql2sqlite/pgsql2sqlite.hpp b/utils/pgsql2sqlite/pgsql2sqlite.hpp
index e339a8f58..9de886732 100644
--- a/utils/pgsql2sqlite/pgsql2sqlite.hpp
+++ b/utils/pgsql2sqlite/pgsql2sqlite.hpp
@@ -352,23 +352,23 @@ void pgsql2sqlite(Connection conn,
                     break;
                 }
                 case 23:
-                    output_rec.push_back(sqlite::value_type(int4net(buf)));
+                    output_rec.emplace_back(int4net(buf));
                     break;
                 case 21:
-                    output_rec.push_back(sqlite::value_type(int2net(buf)));
+                    output_rec.emplace_back(int(int2net(buf)));
                     break;
                 case 700:
                 {
                     float val;
                     float4net(val,buf);
-                    output_rec.push_back(sqlite::value_type(val));
+                    output_rec.emplace_back(double(val));
                     break;
                 }
                 case 701:
                 {
                     double val;
                     float8net(val,buf);
-                    output_rec.push_back(sqlite::value_type(val));
+                    output_rec.emplace_back(val);
                     break;
                 }
                 case 1700:
@@ -377,7 +377,7 @@ void pgsql2sqlite(Connection conn,
                     double val;
                     if (mapnik::util::string2double(str,val))
                     {
-                        output_rec.push_back(sqlite::value_type(val));
+                        output_rec.emplace_back(val);
                     }
                     break;
                 }