diff --git a/include/mapnik/attribute_collector.hpp b/include/mapnik/attribute_collector.hpp
index 6fa698214..637e2c558 100644
--- a/include/mapnik/attribute_collector.hpp
+++ b/include/mapnik/attribute_collector.hpp
@@ -43,6 +43,8 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/algorithm/string/replace.hpp>
 #pragma GCC diagnostic pop
 
@@ -275,8 +277,8 @@ inline void group_attribute_collector::operator() (group_symbolizer const& sym)
     }
 
     // get indexed column names
-    int start = get<value_integer>(sym, keys::start_column);
-    int end = start + get<value_integer>(sym, keys::num_columns);
+    value_integer start = get<value_integer>(sym, keys::start_column);
+    value_integer end = start + get<value_integer>(sym, keys::num_columns);
     for (auto const& col_name : group_columns)
     {
         if (expand_index_columns_ && col_name.find('%') != std::string::npos)
@@ -287,7 +289,7 @@ inline void group_attribute_collector::operator() (group_symbolizer const& sym)
             if (col_name.size() > 1)
             {
                 // Indexed column name. add column name for each index value.
-                for (int col_idx = start; col_idx < end; ++col_idx)
+                for (value_integer col_idx = start; col_idx < end; ++col_idx)
                 {
                     std::string col_idx_str;
                     if (mapnik::util::to_string(col_idx_str,col_idx))
diff --git a/include/mapnik/cairo/cairo_context.hpp b/include/mapnik/cairo/cairo_context.hpp
index f4ca72a0a..9c06d727f 100644
--- a/include/mapnik/cairo/cairo_context.hpp
+++ b/include/mapnik/cairo/cairo_context.hpp
@@ -124,12 +124,12 @@ class cairo_pattern : private util::noncopyable
 public:
     explicit cairo_pattern(image_rgba8 const& data, double opacity = 1.0)
     {
-        int pixels = data.width() * data.height();
+        std::size_t pixels = data.width() * data.height();
         const unsigned int *in_ptr = data.data();
         const unsigned int *in_end = in_ptr + pixels;
         unsigned int *out_ptr;
 
-        surface_ = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, data.width(), data.height());
+        surface_ = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, static_cast<int>(data.width()), static_cast<int>(data.height()));
 
         out_ptr = reinterpret_cast<unsigned int *>(cairo_image_surface_get_data(surface_));
 
diff --git a/include/mapnik/css_color_grammar.hpp b/include/mapnik/css_color_grammar.hpp
index f94d9d1d2..80c5c0a44 100644
--- a/include/mapnik/css_color_grammar.hpp
+++ b/include/mapnik/css_color_grammar.hpp
@@ -49,10 +49,10 @@
 
 BOOST_FUSION_ADAPT_ADT(
     mapnik::color,
-    (unsigned, unsigned, obj.red(), obj.set_red(val))
-    (unsigned, unsigned, obj.green(), obj.set_green(val))
-    (unsigned, unsigned, obj.blue(), obj.set_blue(val))
-    (unsigned, unsigned, obj.alpha(), obj.set_alpha(val))
+    (unsigned, unsigned, obj.red(), obj.set_red(mapnik::safe_cast<uint8_t>(val)))
+    (unsigned, unsigned, obj.green(), obj.set_green(mapnik::safe_cast<uint8_t>(val)))
+    (unsigned, unsigned, obj.blue(), obj.set_blue(mapnik::safe_cast<uint8_t>(val)))
+    (unsigned, unsigned, obj.alpha(), obj.set_alpha(mapnik::safe_cast<uint8_t>(val)))
     )
 
 namespace mapnik
diff --git a/include/mapnik/expression_grammar.hpp b/include/mapnik/expression_grammar.hpp
index 6ce0b5cd6..f2b6b1b6e 100644
--- a/include/mapnik/expression_grammar.hpp
+++ b/include/mapnik/expression_grammar.hpp
@@ -35,6 +35,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/support_locals.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
diff --git a/include/mapnik/geometry_adapters.hpp b/include/mapnik/geometry_adapters.hpp
index c53960bc7..0c7a65713 100644
--- a/include/mapnik/geometry_adapters.hpp
+++ b/include/mapnik/geometry_adapters.hpp
@@ -29,6 +29,9 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
+#pragma GCC diagnostic ignored "-Wunused-parameter"
 #undef B0
 #include <boost/geometry/geometries/register/linestring.hpp>
 #include <boost/geometry/geometries/register/point.hpp>
diff --git a/include/mapnik/geometry_centroid.hpp b/include/mapnik/geometry_centroid.hpp
index 2e7dec199..71d0c0754 100644
--- a/include/mapnik/geometry_centroid.hpp
+++ b/include/mapnik/geometry_centroid.hpp
@@ -50,7 +50,7 @@ struct geometry_centroid
         return false;
     }
 
-    result_type operator() (geometry_collection<T> const& collection) const
+    result_type operator() (geometry_collection<T> const&) const
     {
         return false;
     }
diff --git a/include/mapnik/geometry_correct.hpp b/include/mapnik/geometry_correct.hpp
index 328dc2ed0..dcbb2d7ab 100644
--- a/include/mapnik/geometry_correct.hpp
+++ b/include/mapnik/geometry_correct.hpp
@@ -32,6 +32,8 @@
 #pragma GCC diagnostic ignored "-Wunused-variable"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/geometry/algorithms/correct.hpp>
 #pragma GCC diagnostic pop
 
@@ -73,7 +75,7 @@ struct geometry_correct
     }
 
     template <typename T>
-    result_type operator() (T & geom) const
+    result_type operator() (T &) const
     {
         //no-op
     }
diff --git a/include/mapnik/geometry_reprojection_impl.hpp b/include/mapnik/geometry_reprojection_impl.hpp
index 1e8297ba5..e5ba23f84 100644
--- a/include/mapnik/geometry_reprojection_impl.hpp
+++ b/include/mapnik/geometry_reprojection_impl.hpp
@@ -195,7 +195,7 @@ struct geom_reproj_copy_visitor {
     geometry<T> operator() (line_string<T> const& ls)
     {
         geometry<T> geom; // default empty
-        int intial_err = n_err_;
+        unsigned int intial_err = n_err_;
         line_string<T> new_ls = reproject_internal(ls, proj_trans_, n_err_);
         if (n_err_ > intial_err || new_ls.empty()) return geom;
         geom = std::move(new_ls);
diff --git a/include/mapnik/grid/grid.hpp b/include/mapnik/grid/grid.hpp
index a00479e93..0a1eeb064 100644
--- a/include/mapnik/grid/grid.hpp
+++ b/include/mapnik/grid/grid.hpp
@@ -33,6 +33,7 @@
 #include <mapnik/feature.hpp>
 #include <mapnik/feature_factory.hpp>
 #include <mapnik/util/conversions.hpp>
+#include <mapnik/safe_cast.hpp>
 
 // stl
 #include <map>
@@ -191,12 +192,16 @@ public:
         if (ext0.intersects(ext1))
         {
             box2d<int> box = ext0.intersect(ext1);
-            for (std::size_t y = box.miny(); y < box.maxy(); ++y)
+            std::size_t miny = safe_cast<std::size_t>(box.miny());
+            std::size_t maxy = safe_cast<std::size_t>(box.maxy());
+            std::size_t minx = safe_cast<std::size_t>(box.minx());
+            std::size_t maxx = safe_cast<std::size_t>(box.maxx());
+            for (std::size_t y = miny; y < maxy; ++y)
             {
                 value_type* row_to =  data_.get_row(y);
                 image_rgba8::pixel_type const * row_from = data.get_row(y - y0);
 
-                for (std::size_t x = box.minx(); x < box.maxx(); ++x)
+                for (std::size_t x = minx; x < maxx; ++x)
                 {
                     image_rgba8::pixel_type rgba = row_from[x - x0];
                     unsigned a = (rgba >> 24) & 0xff;
diff --git a/include/mapnik/grid/grid_pixfmt.hpp b/include/mapnik/grid/grid_pixfmt.hpp
index 6f61b9933..d58399476 100644
--- a/include/mapnik/grid/grid_pixfmt.hpp
+++ b/include/mapnik/grid/grid_pixfmt.hpp
@@ -24,9 +24,15 @@
 #define MAPNIK_GRID_PIXFMT_HPP
 
 #include <string>
+#include <mapnik/grid/grid_rendering_buffer.hpp>
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include "agg_basics.h"
 #include <mapnik/grid/grid_pixel.hpp>
-#include <mapnik/grid/grid_rendering_buffer.hpp>
+#pragma GCC diagnostic pop
 
 namespace mapnik
 {
diff --git a/include/mapnik/grid/grid_renderer_base.hpp b/include/mapnik/grid/grid_renderer_base.hpp
index 9524b1661..08a73ad35 100644
--- a/include/mapnik/grid/grid_renderer_base.hpp
+++ b/include/mapnik/grid/grid_renderer_base.hpp
@@ -23,9 +23,14 @@
 #ifndef MAPNIK_GRID_RENDERER_BASE_HPP
 #define MAPNIK_GRID_RENDERER_BASE_HPP
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include "agg_renderer_base.h"
-#include <mapnik/grid/grid_pixfmt.hpp>
 #include <mapnik/grid/grid_pixel.hpp>
+#pragma GCC diagnostic pop
+#include <mapnik/grid/grid_pixfmt.hpp>
 
 namespace mapnik {
 
diff --git a/include/mapnik/image_filter.hpp b/include/mapnik/image_filter.hpp
index 861c7961d..fd94444c2 100644
--- a/include/mapnik/image_filter.hpp
+++ b/include/mapnik/image_filter.hpp
@@ -34,6 +34,8 @@
 #pragma GCC diagnostic ignored "-Wc++11-narrowing"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/gil/gil_all.hpp>
 #pragma GCC diagnostic pop
 
@@ -252,10 +254,10 @@ void apply_convolution_3x3(Src const& src_view, Dst & dst_view, Filter const& fi
     typename Src::x_iterator dst_it = dst_view.row_begin(0);
 
     // top row
-    for (int x = 0 ; x < src_view.width(); ++x)
+    for (std::size_t x = 0 ; x < static_cast<std::size_t>(src_view.width()); ++x)
     {
         (*dst_it)[3] = src_loc[loc11][3]; // Dst.a = Src.a
-        for (int i = 0; i < 3; ++i)
+        for (std::size_t i = 0; i < 3; ++i)
         {
             bits32f p[9];
 
@@ -273,7 +275,7 @@ void apply_convolution_3x3(Src const& src_view, Dst & dst_view, Filter const& fi
                 p[6] = src_loc[loc02][i];
             }
 
-            if ( x == src_view.width()-1)
+            if ( x == static_cast<std::size_t>(src_view.width())-1)
             {
                 p[5] = p[4];
                 p[8] = p[7];
@@ -294,15 +296,15 @@ void apply_convolution_3x3(Src const& src_view, Dst & dst_view, Filter const& fi
         ++dst_it;
     }
     // carrige-return
-    src_loc += point2<std::ptrdiff_t>(-src_view.width(),1);
+    src_loc += point2<std::ptrdiff_t>(-static_cast<std::size_t>(src_view.width()),1);
 
     // 1... height-1 rows
-    for (int y = 1; y<src_view.height()-1; ++y)
+    for (std::size_t y = 1; y<static_cast<std::size_t>(src_view.height())-1; ++y)
     {
-        for (int x = 0; x < src_view.width(); ++x)
+        for (std::size_t x = 0; x < static_cast<std::size_t>(src_view.width()); ++x)
         {
             (*dst_it)[3] = src_loc[loc11][3]; // Dst.a = Src.a
-            for (int i = 0; i < 3; ++i)
+            for (std::size_t i = 0; i < 3; ++i)
             {
                 bits32f p[9];
 
@@ -323,7 +325,7 @@ void apply_convolution_3x3(Src const& src_view, Dst & dst_view, Filter const& fi
                     p[6] = src_loc[loc02][i];
                 }
 
-                if ( x == src_view.width() - 1)
+                if ( x == static_cast<std::size_t>(src_view.width()) - 1)
                 {
                     p[2] = p[1];
                     p[5] = p[4];
@@ -341,15 +343,15 @@ void apply_convolution_3x3(Src const& src_view, Dst & dst_view, Filter const& fi
             ++src_loc.x();
         }
         // carrige-return
-        src_loc += point2<std::ptrdiff_t>(-src_view.width(),1);
+        src_loc += point2<std::ptrdiff_t>(-static_cast<std::size_t>(src_view.width()),1);
     }
 
     // bottom row
-    //src_loc = src_view.xy_at(0,src_view.height()-1);
-    for (int x = 0 ; x < src_view.width(); ++x)
+    //src_loc = src_view.xy_at(0,static_cast<std::size_t>(src_view.height())-1);
+    for (std::size_t x = 0 ; x < static_cast<std::size_t>(src_view.width()); ++x)
     {
         (*dst_it)[3] = src_loc[loc11][3]; // Dst.a = Src.a
-        for (int i = 0; i < 3; ++i)
+        for (std::size_t i = 0; i < 3; ++i)
         {
             bits32f p[9];
 
@@ -367,7 +369,7 @@ void apply_convolution_3x3(Src const& src_view, Dst & dst_view, Filter const& fi
                 p[3] = src_loc[loc01][i];
             }
 
-            if ( x == src_view.width()-1)
+            if ( x == static_cast<std::size_t>(src_view.width())-1)
             {
                 p[2] = p[1];
                 p[5] = p[4];
@@ -429,10 +431,10 @@ void apply_filter(Src & src, color_to_alpha const& op)
     double cr = static_cast<double>(op.color.red())/255.0;
     double cg = static_cast<double>(op.color.green())/255.0;
     double cb = static_cast<double>(op.color.blue())/255.0;
-    for (int y=0; y<src_view.height(); ++y)
+    for (std::size_t y=0; y<static_cast<std::size_t>(src_view.height()); ++y)
     {
-        rgba8_view_t::x_iterator src_it = src_view.row_begin(y);
-        for (int x=0; x<src_view.width(); ++x)
+        rgba8_view_t::x_iterator src_it = src_view.row_begin(static_cast<long>(y));
+        for (std::size_t x=0; x<static_cast<std::size_t>(src_view.width()); ++x)
         {
             uint8_t & r = get_color(src_it[x], red_t());
             uint8_t & g = get_color(src_it[x], green_t());
@@ -490,10 +492,10 @@ void apply_filter(Src & src, colorize_alpha const& op)
         mapnik::filter::color_stop const& stop = op[0];
         mapnik::color const& c = stop.color;
         rgba8_view_t src_view = rgba8_view(src);
-        for (int y=0; y<src_view.height(); ++y)
+        for (std::size_t y=0; y<static_cast<std::size_t>(src_view.height()); ++y)
         {
-            rgba8_view_t::x_iterator src_it = src_view.row_begin(y);
-            for (int x=0; x<src_view.width(); ++x)
+            rgba8_view_t::x_iterator src_it = src_view.row_begin(static_cast<long>(y));
+            for (std::size_t x=0; x<static_cast<std::size_t>(src_view.width()); ++x)
             {
                 uint8_t & r = get_color(src_it[x], red_t());
                 uint8_t & g = get_color(src_it[x], green_t());
@@ -531,10 +533,10 @@ void apply_filter(Src & src, colorize_alpha const& op)
         if (grad_lut.build_lut())
         {
             rgba8_view_t src_view = rgba8_view(src);
-            for (int y=0; y<src_view.height(); ++y)
+            for (std::size_t y=0; y<static_cast<std::size_t>(src_view.height()); ++y)
             {
-                rgba8_view_t::x_iterator src_it = src_view.row_begin(y);
-                for (int x=0; x<src_view.width(); ++x)
+                rgba8_view_t::x_iterator src_it = src_view.row_begin(static_cast<long>(y));
+                for (std::size_t x=0; x<static_cast<std::size_t>(src_view.width()); ++x)
                 {
                     uint8_t & r = get_color(src_it[x], red_t());
                     uint8_t & g = get_color(src_it[x], green_t());
@@ -596,10 +598,10 @@ void apply_filter(Src & src, scale_hsla const& transform)
     if (tinting || set_alpha)
     {
         rgba8_view_t src_view = rgba8_view(src);
-        for (int y=0; y<src_view.height(); ++y)
+        for (std::size_t y=0; y<static_cast<std::size_t>(src_view.height()); ++y)
         {
-            rgba8_view_t::x_iterator src_it = src_view.row_begin(y);
-            for (int x=0; x<src_view.width(); ++x)
+            rgba8_view_t::x_iterator src_it = src_view.row_begin(static_cast<long>(y));
+            for (std::size_t x=0; x<static_cast<std::size_t>(src_view.width()); ++x)
             {
                 uint8_t & r = get_color(src_it[x], red_t());
                 uint8_t & g = get_color(src_it[x], green_t());
@@ -679,10 +681,10 @@ void apply_filter(Src & src, gray const& /*op*/)
 
     rgba8_view_t src_view = rgba8_view(src);
 
-    for (int y=0; y<src_view.height(); ++y)
+    for (std::size_t y=0; y<static_cast<std::size_t>(src_view.height()); ++y)
     {
-        rgba8_view_t::x_iterator src_it = src_view.row_begin(y);
-        for (int x=0; x<src_view.width(); ++x)
+        rgba8_view_t::x_iterator src_it = src_view.row_begin(static_cast<long>(y));
+        for (std::size_t x=0; x<static_cast<std::size_t>(src_view.width()); ++x)
         {
             // formula taken from boost/gil/color_convert.hpp:rgb_to_luminance
             uint8_t & r = get_color(src_it[x], red_t());
@@ -697,22 +699,22 @@ void apply_filter(Src & src, gray const& /*op*/)
 template <typename Src, typename Dst>
 void x_gradient_impl(Src const& src_view, Dst const& dst_view)
 {
-    for (int y=0; y<src_view.height(); ++y)
+    for (std::size_t y=0; y<static_cast<std::size_t>(src_view.height()); ++y)
     {
-        typename Src::x_iterator src_it = src_view.row_begin(y);
-        typename Dst::x_iterator dst_it = dst_view.row_begin(y);
+        typename Src::x_iterator src_it = src_view.row_begin(static_cast<long>(y));
+        typename Dst::x_iterator dst_it = dst_view.row_begin(static_cast<long>(y));
 
         dst_it[0][0] = 128 + (src_it[0][0] - src_it[1][0]) / 2;
         dst_it[0][1] = 128 + (src_it[0][1] - src_it[1][1]) / 2;
         dst_it[0][2] = 128 + (src_it[0][2] - src_it[1][2]) / 2;
 
-        dst_it[dst_view.width()-1][0] = 128 + (src_it[src_view.width()-2][0] - src_it[src_view.width()-1][0]) / 2;
-        dst_it[dst_view.width()-1][1] = 128 + (src_it[src_view.width()-2][1] - src_it[src_view.width()-1][1]) / 2;
-        dst_it[dst_view.width()-1][2] = 128 + (src_it[src_view.width()-2][2] - src_it[src_view.width()-1][2]) / 2;
+        dst_it[dst_view.width()-1][0] = 128 + (src_it[static_cast<std::size_t>(src_view.width())-2][0] - src_it[static_cast<std::size_t>(src_view.width())-1][0]) / 2;
+        dst_it[dst_view.width()-1][1] = 128 + (src_it[static_cast<std::size_t>(src_view.width())-2][1] - src_it[static_cast<std::size_t>(src_view.width())-1][1]) / 2;
+        dst_it[dst_view.width()-1][2] = 128 + (src_it[static_cast<std::size_t>(src_view.width())-2][2] - src_it[static_cast<std::size_t>(src_view.width())-1][2]) / 2;
 
-        dst_it[0][3] = dst_it[src_view.width()-1][3] = 255;
+        dst_it[0][3] = dst_it[static_cast<std::size_t>(src_view.width())-1][3] = 255;
 
-        for (int x=1; x<src_view.width()-1; ++x)
+        for (std::size_t x=1; x<static_cast<std::size_t>(src_view.width())-1; ++x)
         {
             dst_it[x][0] = 128 + (src_it[x-1][0] - src_it[x+1][0]) / 2;
             dst_it[x][1] = 128 + (src_it[x-1][1] - src_it[x+1][1]) / 2;
@@ -744,10 +746,10 @@ void apply_filter(Src & src, invert const& /*op*/)
 
     rgba8_view_t src_view = rgba8_view(src);
 
-    for (int y=0; y<src_view.height(); ++y)
+    for (std::size_t y=0; y<static_cast<std::size_t>(src_view.height()); ++y)
     {
-        rgba8_view_t::x_iterator src_it = src_view.row_begin(y);
-        for (int x=0; x<src_view.width(); ++x)
+        rgba8_view_t::x_iterator src_it = src_view.row_begin(static_cast<long>(y));
+        for (std::size_t x=0; x<static_cast<std::size_t>(src_view.width()); ++x)
         {
             // we only work with premultiplied source,
             // thus all color values must be <= alpha
diff --git a/include/mapnik/image_filter_grammar.hpp b/include/mapnik/image_filter_grammar.hpp
index ec00f1ee3..9e99cf103 100644
--- a/include/mapnik/image_filter_grammar.hpp
+++ b/include/mapnik/image_filter_grammar.hpp
@@ -28,6 +28,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/fusion/include/adapt_struct.hpp>
 #pragma GCC diagnostic pop
diff --git a/include/mapnik/image_filter_grammar_impl.hpp b/include/mapnik/image_filter_grammar_impl.hpp
index c88089f90..be43ef1e9 100644
--- a/include/mapnik/image_filter_grammar_impl.hpp
+++ b/include/mapnik/image_filter_grammar_impl.hpp
@@ -25,7 +25,10 @@
 #include <mapnik/image_filter_grammar.hpp>
 
 // spirit
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
 #include <boost/spirit/include/phoenix.hpp>
+#pragma GCC diagnostic pop
 
 namespace mapnik {
 
diff --git a/include/mapnik/image_null.hpp b/include/mapnik/image_null.hpp
index 285a57910..df259a5bf 100644
--- a/include/mapnik/image_null.hpp
+++ b/include/mapnik/image_null.hpp
@@ -42,34 +42,34 @@ public:
 private:
 public:
     image() {}
-    image(int width,
-          int height,
-          bool initialize = true,
-          bool premultiplied = false,
-          bool painted = false) {}
-    image(image<null_t> const& rhs) {}
-    image(image<null_t> && rhs) noexcept {}
-    image<null_t>& operator=(image<null_t> rhs) { return *this; }
+    image(int /*width*/,
+          int /*height*/,
+          bool /*initialize*/ = true,
+          bool /*premultiplied*/ = false,
+          bool /*painted*/ = false) {}
+    image(image<null_t> const&) {}
+    image(image<null_t> &&) noexcept {}
+    image<null_t>& operator=(image<null_t>) { return *this; }
     image<null_t>const& operator=(image<null_t> const& rhs) const { return rhs; }
-    bool operator==(image<null_t> const& rhs) const { return true; }
-    bool operator<(image<null_t> const& rhs) const { return false; }
+    bool operator==(image<null_t> const&) const { return true; }
+    bool operator<(image<null_t> const&) const { return false; }
 
     std::size_t width() const { return 0; }
     std::size_t height() const { return 0; }
     std::size_t size() const { return 0; }
     std::size_t row_size() const { return 0; }
-    void set(pixel_type const& t) { throw std::runtime_error("Can not set values for null image"); }
-    pixel_type& operator() (std::size_t i, std::size_t j) { throw std::runtime_error("Can not get or set values for null image"); }
-    pixel_type const& operator() (std::size_t i, std::size_t j) const { throw std::runtime_error("Can not get or set values for null image"); }
+    void set(pixel_type const&) { throw std::runtime_error("Can not set values for null image"); }
+    pixel_type& operator() (std::size_t, std::size_t) { throw std::runtime_error("Can not get or set values for null image"); }
+    pixel_type const& operator() (std::size_t, std::size_t) const { throw std::runtime_error("Can not get or set values for null image"); }
     unsigned const char* bytes() const { return nullptr; }
     unsigned char* bytes() {return nullptr; }
     double get_offset() const { return 0.0; }
-    void set_offset(double set) {}
+    void set_offset(double) {}
     double get_scaling() const { return 1.0; }
-    void set_scaling(double set) {}
+    void set_scaling(double) {}
     bool get_premultiplied() const { return false; }
-    void set_premultiplied(bool set) {}
-    void painted(bool painted) {}
+    void set_premultiplied(bool) {}
+    void painted(bool) {}
     bool painted() const { return false; }
     image_dtype get_dtype() const { return dtype; }
 };
diff --git a/include/mapnik/image_view_null.hpp b/include/mapnik/image_view_null.hpp
index 1ad6c3d04..aad3e9eb2 100644
--- a/include/mapnik/image_view_null.hpp
+++ b/include/mapnik/image_view_null.hpp
@@ -40,20 +40,20 @@ public:
     image_view() {}
     ~image_view() {};
 
-    image_view(image_view<image_null> const& rhs) {}
-    image_view<image_null> & operator=(image_view<image_null> const& rhs) { return *this; }
-    bool operator==(image_view<image_null> const& rhs) const { return true; }
-    bool operator<(image_view<image_null> const& rhs) const { return false; }
+    image_view(image_view<image_null> const&) {}
+    image_view<image_null> & operator=(image_view<image_null> const&) { return *this; }
+    bool operator==(image_view<image_null> const&) const { return true; }
+    bool operator<(image_view<image_null> const&) const { return false; }
 
     std::size_t x() const { return 0; }
     std::size_t y() const { return 0; }
     std::size_t width() const { return 0; }
     std::size_t height() const { return 0; }
-    pixel_type operator() (std::size_t i, std::size_t j) const { throw std::runtime_error("Can not get from a null image view"); }
+    pixel_type operator() (std::size_t, std::size_t) const { throw std::runtime_error("Can not get from a null image view"); }
     std::size_t size() const { return 0; }
     std::size_t row_size() const { return 0; }
-    const pixel_type* get_row(std::size_t row) const { return nullptr; }
-    const pixel_type* get_row(std::size_t row, std::size_t x0) const { return nullptr; }
+    const pixel_type* get_row(std::size_t) const { return nullptr; }
+    const pixel_type* get_row(std::size_t, std::size_t) const { return nullptr; }
     bool get_premultiplied() const { return false; }
     double get_offset() const { return 0.0; }
     double get_scaling() const { return 1.0; }
diff --git a/include/mapnik/json/error_handler.hpp b/include/mapnik/json/error_handler.hpp
index 74b0aa48d..1925002a3 100644
--- a/include/mapnik/json/error_handler.hpp
+++ b/include/mapnik/json/error_handler.hpp
@@ -25,7 +25,10 @@
 
 #include <string>
 #include <sstream>
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
 #include <boost/spirit/home/support/info.hpp>
+#pragma GCC diagnostic pop
 
 namespace mapnik { namespace json {
 
diff --git a/include/mapnik/json/extract_bounding_box_grammar.hpp b/include/mapnik/json/extract_bounding_box_grammar.hpp
index 1e061e706..2183fe501 100644
--- a/include/mapnik/json/extract_bounding_box_grammar.hpp
+++ b/include/mapnik/json/extract_bounding_box_grammar.hpp
@@ -33,6 +33,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
 #include <boost/fusion/adapted/std_tuple.hpp>
diff --git a/include/mapnik/json/feature_generator_grammar.hpp b/include/mapnik/json/feature_generator_grammar.hpp
index 3852c7ba6..d543c206c 100644
--- a/include/mapnik/json/feature_generator_grammar.hpp
+++ b/include/mapnik/json/feature_generator_grammar.hpp
@@ -84,8 +84,8 @@ template <typename T>
 struct get_id
 {
     using feature_type = T;
-    using result_type = int;
-    int operator() (feature_type const& f) const
+    using result_type = mapnik::value_integer;
+    result_type operator() (feature_type const& f) const
     {
         return f.id();
     }
diff --git a/include/mapnik/json/feature_grammar.hpp b/include/mapnik/json/feature_grammar.hpp
index 08eb39df1..94915af02 100644
--- a/include/mapnik/json/feature_grammar.hpp
+++ b/include/mapnik/json/feature_grammar.hpp
@@ -31,10 +31,13 @@
 #include <mapnik/value.hpp>
 #include <mapnik/json/generic_json.hpp>
 #include <mapnik/json/value_converters.hpp>
-// spirit::qi
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/include/support_line_pos_iterator.hpp>
+#pragma GCC diagnostic pop
 
 namespace mapnik { namespace json {
 
diff --git a/include/mapnik/json/generic_json.hpp b/include/mapnik/json/generic_json.hpp
index edb1284f4..c9fbf822c 100644
--- a/include/mapnik/json/generic_json.hpp
+++ b/include/mapnik/json/generic_json.hpp
@@ -31,6 +31,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix.hpp>
 #pragma GCC diagnostic pop
diff --git a/include/mapnik/json/geometry_generator_grammar.hpp b/include/mapnik/json/geometry_generator_grammar.hpp
index 51990add4..f325f2f86 100644
--- a/include/mapnik/json/geometry_generator_grammar.hpp
+++ b/include/mapnik/json/geometry_generator_grammar.hpp
@@ -33,6 +33,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
 #include <boost/math/special_functions/trunc.hpp> // for vc++ and android whose c++11 libs lack std::trunc
diff --git a/include/mapnik/json/positions_grammar.hpp b/include/mapnik/json/positions_grammar.hpp
index 3440d820c..3e67c31c2 100644
--- a/include/mapnik/json/positions_grammar.hpp
+++ b/include/mapnik/json/positions_grammar.hpp
@@ -34,6 +34,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
 #include <boost/fusion/adapted/std_tuple.hpp>
diff --git a/include/mapnik/json/properties_generator_grammar.hpp b/include/mapnik/json/properties_generator_grammar.hpp
index ea5da9332..08a397484 100644
--- a/include/mapnik/json/properties_generator_grammar.hpp
+++ b/include/mapnik/json/properties_generator_grammar.hpp
@@ -32,6 +32,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma.hpp>
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
diff --git a/include/mapnik/json/topojson_grammar.hpp b/include/mapnik/json/topojson_grammar.hpp
index bf8d24101..b180bdc8f 100644
--- a/include/mapnik/json/topojson_grammar.hpp
+++ b/include/mapnik/json/topojson_grammar.hpp
@@ -34,6 +34,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
 #pragma GCC diagnostic pop
diff --git a/include/mapnik/marker.hpp b/include/mapnik/marker.hpp
index 3eaaebec8..7ef699338 100644
--- a/include/mapnik/marker.hpp
+++ b/include/mapnik/marker.hpp
@@ -70,19 +70,19 @@ public:
 
     box2d<double> bounding_box() const
     {
-        double width = bitmap_data_.width();
-        double height = bitmap_data_.height();
-        return box2d<double>(0, 0, width, height);
+        std::size_t width = bitmap_data_.width();
+        std::size_t height = bitmap_data_.height();
+        return box2d<double>(static_cast<double>(0), static_cast<double>(0), static_cast<double>(width), static_cast<double>(height));
     }
 
-    inline std::size_t width() const
+    inline double width() const
     {
-        return bitmap_data_.width();
+        return static_cast<double>(bitmap_data_.width());
     }
 
-    inline std::size_t height() const
+    inline double height() const
     {
-        return bitmap_data_.height();
+        return static_cast<double>(bitmap_data_.height());
     }
 
     image_rgba8 const& get_data() const
@@ -169,7 +169,7 @@ struct get_marker_width_visitor
     template <typename T>
     double operator()(T const& data) const
     {
-        return static_cast<double>(data.width());
+        return data.width();
     }
 };
 
@@ -178,7 +178,7 @@ struct get_marker_height_visitor
     template <typename T>
     double operator()(T const& data) const
     {
-        return static_cast<double>(data.height());
+        return data.height();
     }
 };
 
diff --git a/include/mapnik/palette.hpp b/include/mapnik/palette.hpp
index cf21338ac..ae88c146f 100644
--- a/include/mapnik/palette.hpp
+++ b/include/mapnik/palette.hpp
@@ -30,6 +30,8 @@
 
 #define USE_DENSE_HASH_MAP
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
 #ifdef USE_DENSE_HASH_MAP
     #include <mapnik/sparsehash/dense_hash_map>
     using rgba_hash_table = google::dense_hash_map<unsigned int, unsigned char>;
@@ -37,6 +39,7 @@
     #include <boost/unordered_map.hpp>
     using rgba_hash_table = boost::unordered_map<unsigned int, unsigned char>;
 #endif
+#pragma GCC diagnostic pop
 
 // stl
 #include <vector>
diff --git a/include/mapnik/params_impl.hpp b/include/mapnik/params_impl.hpp
index 255521fec..16170bab0 100644
--- a/include/mapnik/params_impl.hpp
+++ b/include/mapnik/params_impl.hpp
@@ -34,6 +34,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/optional.hpp>
 #include <boost/lexical_cast.hpp>
 #pragma GCC diagnostic pop
diff --git a/include/mapnik/path.hpp b/include/mapnik/path.hpp
index b57fe509f..8f43ae73b 100644
--- a/include/mapnik/path.hpp
+++ b/include/mapnik/path.hpp
@@ -124,7 +124,7 @@ struct vertex_adapter : private util::noncopyable
 
     unsigned vertex(double* x, double* y) const
     {
-        return path_.cont_.get_vertex(itr_++,x,y);
+        return path_.cont_.get_vertex(static_cast<unsigned>(itr_++),x,y);
     }
 
     unsigned vertex(std::size_t index, double* x, double* y) const
diff --git a/include/mapnik/path_expression_grammar.hpp b/include/mapnik/path_expression_grammar.hpp
index a69f535a2..4f5654fda 100644
--- a/include/mapnik/path_expression_grammar.hpp
+++ b/include/mapnik/path_expression_grammar.hpp
@@ -31,6 +31,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #pragma GCC diagnostic pop
 
diff --git a/include/mapnik/proj_strategy.hpp b/include/mapnik/proj_strategy.hpp
index 2afb17052..3d7100c0f 100644
--- a/include/mapnik/proj_strategy.hpp
+++ b/include/mapnik/proj_strategy.hpp
@@ -32,6 +32,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/geometry/core/coordinate_type.hpp>
 #include <boost/geometry/core/access.hpp>
 #include <boost/numeric/conversion/cast.hpp>
diff --git a/include/mapnik/quad_tree.hpp b/include/mapnik/quad_tree.hpp
index 474ee2e7c..84fd4382d 100644
--- a/include/mapnik/quad_tree.hpp
+++ b/include/mapnik/quad_tree.hpp
@@ -32,6 +32,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/ptr_container/ptr_vector.hpp>
 #pragma GCC diagnostic pop
 
diff --git a/include/mapnik/renderer_common/pattern_alignment.hpp b/include/mapnik/renderer_common/pattern_alignment.hpp
index 53084b824..12f746d32 100644
--- a/include/mapnik/renderer_common/pattern_alignment.hpp
+++ b/include/mapnik/renderer_common/pattern_alignment.hpp
@@ -51,7 +51,7 @@ struct apply_local_alignment
     }
 
     template <typename Adapter>
-    void operator() (Adapter & va)
+    void operator() (Adapter &)
     {
         // no-op
     }
diff --git a/include/mapnik/renderer_common/process_group_symbolizer.hpp b/include/mapnik/renderer_common/process_group_symbolizer.hpp
index 00017301a..40549cdf3 100644
--- a/include/mapnik/renderer_common/process_group_symbolizer.hpp
+++ b/include/mapnik/renderer_common/process_group_symbolizer.hpp
@@ -280,9 +280,9 @@ void render_group_symbolizer(group_symbolizer const& sym,
 
     // run feature or sub feature through the group rules & symbolizers
     // for each index value in the range
-    int start = get<value_integer>(sym, keys::start_column);
-    int end = start + get<value_integer>(sym, keys::num_columns);
-    for (int col_idx = start; col_idx < end; ++col_idx)
+    value_integer start = get<value_integer>(sym, keys::start_column);
+    value_integer end = start + get<value_integer>(sym, keys::num_columns);
+    for (value_integer col_idx = start; col_idx < end; ++col_idx)
     {
         // create sub feature with indexed column values
         feature_ptr sub_feature = feature_factory::create(sub_feature_ctx, col_idx);
@@ -295,7 +295,7 @@ void render_group_symbolizer(group_symbolizer const& sym,
                 if (col_name.size() == 1)
                 {
                     // column name is '%' by itself, so give the index as the value
-                    sub_feature->put(col_name, (value_integer)col_idx);
+                    sub_feature->put(col_name, col_idx);
                 }
                 else
                 {
diff --git a/include/mapnik/sql_utils.hpp b/include/mapnik/sql_utils.hpp
index 543ea25ee..b53f06bf2 100644
--- a/include/mapnik/sql_utils.hpp
+++ b/include/mapnik/sql_utils.hpp
@@ -31,6 +31,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/algorithm/string/replace.hpp>
 #pragma GCC diagnostic pop
 
diff --git a/include/mapnik/svg/geometry_svg_generator.hpp b/include/mapnik/svg/geometry_svg_generator.hpp
index 3f75d8444..d43022966 100644
--- a/include/mapnik/svg/geometry_svg_generator.hpp
+++ b/include/mapnik/svg/geometry_svg_generator.hpp
@@ -38,6 +38,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma.hpp>
 #include <boost/spirit/include/phoenix_core.hpp>
 #include <boost/spirit/include/phoenix_operator.hpp>
diff --git a/include/mapnik/svg/output/svg_output_grammars.hpp b/include/mapnik/svg/output/svg_output_grammars.hpp
index ce1afe760..6d9aff566 100644
--- a/include/mapnik/svg/output/svg_output_grammars.hpp
+++ b/include/mapnik/svg/output/svg_output_grammars.hpp
@@ -41,6 +41,8 @@ namespace mapnik { namespace svg {
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma_nonterminal.hpp>
 #include <boost/spirit/include/karma_rule.hpp>
 #include <boost/fusion/adapted/struct.hpp>
diff --git a/include/mapnik/svg/output/svg_output_grammars_impl.hpp b/include/mapnik/svg/output/svg_output_grammars_impl.hpp
index ab41aabae..f6647c3f6 100644
--- a/include/mapnik/svg/output/svg_output_grammars_impl.hpp
+++ b/include/mapnik/svg/output/svg_output_grammars_impl.hpp
@@ -31,6 +31,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma.hpp>
 #include <boost/fusion/include/std_pair.hpp>
 #pragma GCC diagnostic pop
diff --git a/include/mapnik/svg/svg_converter.hpp b/include/mapnik/svg/svg_converter.hpp
index ddde41d82..a88b30b3d 100644
--- a/include/mapnik/svg/svg_converter.hpp
+++ b/include/mapnik/svg/svg_converter.hpp
@@ -27,6 +27,7 @@
 #include <mapnik/svg/svg_path_attributes.hpp>
 #include <mapnik/svg/svg_path_adapter.hpp>
 #include <mapnik/util/noncopyable.hpp>
+#include <mapnik/safe_cast.hpp>
 
 // agg
 #include "agg_path_storage.h"
@@ -57,8 +58,8 @@ public:
 
     void begin_path()
     {
-        unsigned idx = source_.start_new_path();
-        attributes_.add(path_attributes(cur_attr(), idx));
+        std::size_t idx = source_.start_new_path();
+        attributes_.add(path_attributes(cur_attr(), safe_cast<unsigned>(idx)));
     }
 
     void end_path()
@@ -91,7 +92,7 @@ public:
         double y2 = 0.0;
         if(source_.total_vertices())
         {
-            source_.vertex(source_.total_vertices() - 1, &x2, &y2);
+            source_.vertex(safe_cast<unsigned>(source_.total_vertices() - 1), &x2, &y2);
             if(rel) x += x2;
             source_.line_to(x, y2);
         }
@@ -103,7 +104,7 @@ public:
         double y2 = 0.0;
         if(source_.total_vertices())
         {
-            source_.vertex(source_.total_vertices() - 1, &x2, &y2);
+            source_.vertex(safe_cast<unsigned>(source_.total_vertices() - 1), &x2, &y2);
             if(rel) y += y2;
             source_.line_to(x2, y);
         }
diff --git a/include/mapnik/svg/svg_path_adapter.hpp b/include/mapnik/svg/svg_path_adapter.hpp
index 72fa29a65..26383fcd0 100644
--- a/include/mapnik/svg/svg_path_adapter.hpp
+++ b/include/mapnik/svg/svg_path_adapter.hpp
@@ -26,6 +26,8 @@
 // mapnik
 #include <mapnik/util/noncopyable.hpp>
 #include <mapnik/box2d.hpp>
+#include <mapnik/safe_cast.hpp>
+
 // agg
 #include "agg_math.h"
 #include "agg_array.h"
@@ -53,7 +55,7 @@ public:
 
     // Make path functions
     //--------------------------------------------------------------------
-    unsigned start_new_path();
+    std::size_t start_new_path();
 
     void move_to(double x, double y);
     void move_rel(double dx, double dy);
@@ -112,7 +114,7 @@ public:
     const container_type& vertices() const { return vertices_; }
     container_type& vertices()       { return vertices_; }
 
-    unsigned total_vertices() const;
+    std::size_t total_vertices() const;
 
     void rel_to_abs(double* x, double* y) const;
 
@@ -263,7 +265,7 @@ private:
 
 //------------------------------------------------------------------------
 template<class VC>
-unsigned path_adapter<VC>::start_new_path()
+std::size_t path_adapter<VC>::start_new_path()
 {
     if(!is_stop(vertices_.last_command()))
     {
@@ -547,7 +549,7 @@ inline void path_adapter<VC>::close_polygon(unsigned flags)
 
 //------------------------------------------------------------------------
 template<class VC>
-inline unsigned path_adapter<VC>::total_vertices() const
+inline std::size_t path_adapter<VC>::total_vertices() const
 {
     return vertices_.total_vertices();
 }
@@ -886,7 +888,7 @@ public:
     {
         return vertices_.size() ?
             vertices_[vertices_.size() - 1].cmd :
-            (unsigned)path_cmd_stop;
+            path_cmd_stop;
     }
 
     unsigned last_vertex(double* x, double* y) const
@@ -896,7 +898,7 @@ public:
             *x = *y = 0.0;
             return path_cmd_stop;
         }
-        return vertex(vertices_.size() - 1, x, y);
+        return vertex(safe_cast<unsigned>(vertices_.size() - 1), x, y);
     }
 
     unsigned prev_vertex(double* x, double* y) const
@@ -906,7 +908,7 @@ public:
             *x = *y = 0.0;
             return path_cmd_stop;
         }
-        return vertex(vertices_.size() - 2, x, y);
+        return vertex(safe_cast<unsigned>(vertices_.size() - 2), x, y);
     }
 
     double last_x() const
diff --git a/include/mapnik/svg/svg_path_commands.hpp b/include/mapnik/svg/svg_path_commands.hpp
index ff398368b..9c5266c59 100644
--- a/include/mapnik/svg/svg_path_commands.hpp
+++ b/include/mapnik/svg/svg_path_commands.hpp
@@ -31,6 +31,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
 #include <boost/spirit/include/phoenix_core.hpp>
diff --git a/include/mapnik/svg/svg_renderer_agg.hpp b/include/mapnik/svg/svg_renderer_agg.hpp
index 569f3fa35..653f3c223 100644
--- a/include/mapnik/svg/svg_renderer_agg.hpp
+++ b/include/mapnik/svg/svg_renderer_agg.hpp
@@ -27,10 +27,16 @@
 #include <mapnik/svg/svg_path_attributes.hpp>
 #include <mapnik/gradient.hpp>
 #include <mapnik/box2d.hpp>
+#include <mapnik/value_types.hpp>
 #include <mapnik/util/noncopyable.hpp>
 
 #if defined(GRID_RENDERER)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <mapnik/grid/grid_pixel.hpp>
+#pragma GCC diagnostic pop
 #endif
 
 // agg
@@ -341,7 +347,7 @@ public:
     void render_id(Rasterizer& ras,
                    Scanline& sl,
                    Renderer& ren,
-                   int feature_id,
+                   mapnik::value_integer feature_id,
                    agg::trans_affine const& mtx,
                    double /*opacity*/,
                    box2d<double> const& /*symbol_bbox*/)
diff --git a/include/mapnik/svg/svg_transform_grammar.hpp b/include/mapnik/svg/svg_transform_grammar.hpp
index 68ed02198..9e4f6f661 100644
--- a/include/mapnik/svg/svg_transform_grammar.hpp
+++ b/include/mapnik/svg/svg_transform_grammar.hpp
@@ -34,6 +34,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
 #include <boost/spirit/include/phoenix_core.hpp>
diff --git a/include/mapnik/text/face.hpp b/include/mapnik/text/face.hpp
index 31dd45aa2..5f636bb81 100644
--- a/include/mapnik/text/face.hpp
+++ b/include/mapnik/text/face.hpp
@@ -87,7 +87,7 @@ public:
     void set_character_sizes(double size);
     void set_unscaled_character_sizes();
 
-    unsigned size() const { return faces_.size(); }
+    std::size_t size() const { return faces_.size(); }
     iterator begin() { return faces_.begin(); }
     iterator end() { return faces_.end(); }
 private:
diff --git a/include/mapnik/text/placements/list.hpp b/include/mapnik/text/placements/list.hpp
index 1fa4c8712..993012d5d 100644
--- a/include/mapnik/text/placements/list.hpp
+++ b/include/mapnik/text/placements/list.hpp
@@ -38,7 +38,7 @@ public:
     virtual void add_expressions(expression_set & output) const;
     text_symbolizer_properties & add();
     text_symbolizer_properties & get(unsigned i);
-    unsigned size() const;
+    std::size_t size() const;
     static text_placements_ptr from_xml(xml_node const& xml, fontset_map const& fontsets, bool is_shield);
 private:
     std::vector<text_symbolizer_properties> list_;
diff --git a/include/mapnik/text/symbolizer_helpers.hpp b/include/mapnik/text/symbolizer_helpers.hpp
index ce31a04b7..fc5279fe6 100644
--- a/include/mapnik/text/symbolizer_helpers.hpp
+++ b/include/mapnik/text/symbolizer_helpers.hpp
@@ -90,7 +90,7 @@ protected:
     view_transform const& t_;
     box2d<double> dims_;
     box2d<double> const& query_extent_;
-    float scale_factor_;
+    double scale_factor_;
 
     //Processing
     // Remaining geometries to be processed.
diff --git a/include/mapnik/util/container_adapter.hpp b/include/mapnik/util/container_adapter.hpp
index da47b2ec5..d508190e9 100644
--- a/include/mapnik/util/container_adapter.hpp
+++ b/include/mapnik/util/container_adapter.hpp
@@ -32,6 +32,8 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/support_container.hpp>
 #pragma GCC diagnostic pop
 
diff --git a/include/mapnik/util/hsl.hpp b/include/mapnik/util/hsl.hpp
index e0b2d598a..40c212355 100644
--- a/include/mapnik/util/hsl.hpp
+++ b/include/mapnik/util/hsl.hpp
@@ -59,7 +59,7 @@ inline double hue_to_rgb(double m1, double m2, double h)
 
 inline void hsl2rgb(double h, double s, double l,
                     double & r, double & g, double & b) {
-    if (!s) {
+    if (s == 0.0) {
         r = g = b = l;
     }
     else
diff --git a/include/mapnik/util/path_iterator.hpp b/include/mapnik/util/path_iterator.hpp
index 840e63ac4..b2d70ca0e 100644
--- a/include/mapnik/util/path_iterator.hpp
+++ b/include/mapnik/util/path_iterator.hpp
@@ -111,7 +111,7 @@ private:
 
     void increment()
     {
-        std::get<0>(v_) = vertices_->cont_.get_vertex(pos_++, &std::get<1>(v_), &std::get<2>(v_));
+        std::get<0>(v_) = vertices_->cont_.get_vertex(static_cast<unsigned>(pos_++), &std::get<1>(v_), &std::get<2>(v_));
     }
 
     bool equal( path_iterator const& other) const
diff --git a/include/mapnik/vertex_converters.hpp b/include/mapnik/vertex_converters.hpp
index 1380bd55e..7b35e3a72 100644
--- a/include/mapnik/vertex_converters.hpp
+++ b/include/mapnik/vertex_converters.hpp
@@ -325,7 +325,7 @@ struct converters_helper<Dispatcher>
     template <typename Converter>
     static void set(Dispatcher &, std::size_t) {}
     template <typename Geometry, typename Processor>
-    static void forward(Dispatcher & disp, Geometry & geom, Processor & proc)
+    static void forward(Dispatcher &, Geometry & geom, Processor & proc)
     {
         proc.add_path(geom);
     }
diff --git a/include/mapnik/wkt/wkt_generator_grammar.hpp b/include/mapnik/wkt/wkt_generator_grammar.hpp
index 0d4286ed4..e4a396959 100644
--- a/include/mapnik/wkt/wkt_generator_grammar.hpp
+++ b/include/mapnik/wkt/wkt_generator_grammar.hpp
@@ -34,6 +34,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
 #include <boost/math/special_functions/trunc.hpp> // for vc++ and android whose c++11 libs lack std::trunc
diff --git a/include/mapnik/wkt/wkt_grammar.hpp b/include/mapnik/wkt/wkt_grammar.hpp
index c2245631c..43c5334a1 100644
--- a/include/mapnik/wkt/wkt_grammar.hpp
+++ b/include/mapnik/wkt/wkt_grammar.hpp
@@ -30,6 +30,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/assert.hpp>
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix_function.hpp>
diff --git a/include/mapnik/xml_attribute_cast.hpp b/include/mapnik/xml_attribute_cast.hpp
index 1a3cb98f2..bc515c525 100644
--- a/include/mapnik/xml_attribute_cast.hpp
+++ b/include/mapnik/xml_attribute_cast.hpp
@@ -37,7 +37,10 @@
 #include <mapnik/text/font_feature_settings.hpp>
 
 // boost
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
 #include <boost/optional.hpp>
+#pragma GCC diagnostic pop
 
 // stl
 #include <string>
@@ -166,7 +169,7 @@ struct do_xml_attribute_cast<mapnik::enumeration<T,MAX> >
 template <>
 struct do_xml_attribute_cast<mapnik::color>
 {
-    static inline boost::optional<mapnik::color> xml_attribute_cast_impl(xml_tree const& tree, std::string const& source)
+    static inline boost::optional<mapnik::color> xml_attribute_cast_impl(xml_tree const&, std::string const& source)
     {
         return parse_color(source);
     }
@@ -176,7 +179,7 @@ struct do_xml_attribute_cast<mapnik::color>
 template <>
 struct do_xml_attribute_cast<std::string>
 {
-    static inline boost::optional<std::string> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& source)
+    static inline boost::optional<std::string> xml_attribute_cast_impl(xml_tree const&, std::string const& source)
     {
         return boost::optional<std::string>(source);
     }
@@ -206,7 +209,7 @@ struct do_xml_attribute_cast<mapnik::expression_ptr>
 template <>
 struct do_xml_attribute_cast<mapnik::font_feature_settings>
 {
-    static inline boost::optional<mapnik::font_feature_settings> xml_attribute_cast_impl(xml_tree const& tree, std::string const& source)
+    static inline boost::optional<mapnik::font_feature_settings> xml_attribute_cast_impl(xml_tree const&, std::string const& source)
     {
         return mapnik::font_feature_settings(source);
     }
diff --git a/include/mapnik/xml_tree.hpp b/include/mapnik/xml_tree.hpp
index f13cd4170..8f2d177de 100644
--- a/include/mapnik/xml_tree.hpp
+++ b/include/mapnik/xml_tree.hpp
@@ -36,7 +36,7 @@ namespace mapnik
 class MAPNIK_DECL xml_tree
 {
 public:
-    xml_tree(std::string const& encoding="utf8");
+    xml_tree();
     void set_filename(std::string const& fn);
     std::string const& filename() const;
     xml_node &root();
diff --git a/plugins/input/csv/csv_utils.hpp b/plugins/input/csv/csv_utils.hpp
index 3ec8c9fcb..34583236c 100644
--- a/plugins/input/csv/csv_utils.hpp
+++ b/plugins/input/csv/csv_utils.hpp
@@ -26,6 +26,7 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
 #include <boost/algorithm/string.hpp>
 #pragma GCC diagnostic pop
 
diff --git a/plugins/input/geojson/geojson_datasource.hpp b/plugins/input/geojson/geojson_datasource.hpp
index 66c54e907..fc060ba5e 100644
--- a/plugins/input/geojson/geojson_datasource.hpp
+++ b/plugins/input/geojson/geojson_datasource.hpp
@@ -40,6 +40,8 @@
 #pragma GCC diagnostic ignored "-Wunused-variable"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/version.hpp>
 #include <boost/geometry/index/rtree.hpp>
 #pragma GCC diagnostic pop
diff --git a/plugins/input/shape/dbfile.cpp b/plugins/input/shape/dbfile.cpp
index 2da4978a6..f042d7a4b 100644
--- a/plugins/input/shape/dbfile.cpp
+++ b/plugins/input/shape/dbfile.cpp
@@ -32,6 +32,7 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
+#pragma GCC diagnostic ignored "-Wshadow"
 #include <boost/spirit/include/qi.hpp>
 #ifdef SHAPE_MEMORY_MAPPED_FILE
 #include <boost/interprocess/mapped_region.hpp>
diff --git a/plugins/input/shape/dbfile.hpp b/plugins/input/shape/dbfile.hpp
index 75e77d323..ca8ec82d9 100644
--- a/plugins/input/shape/dbfile.hpp
+++ b/plugins/input/shape/dbfile.hpp
@@ -29,11 +29,11 @@
 #include <mapnik/unicode.hpp>
 #ifdef SHAPE_MEMORY_MAPPED_FILE
 #include <mapnik/mapped_memory_cache.hpp>
-#endif
-
-
-// boost
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wshadow"
 #include <boost/interprocess/streams/bufferstream.hpp>
+#pragma GCC diagnostic pop
+#endif
 
 // stl
 #include <vector>
diff --git a/plugins/input/shape/shapefile.hpp b/plugins/input/shape/shapefile.hpp
index 78b2deb1b..b285b6790 100644
--- a/plugins/input/shape/shapefile.hpp
+++ b/plugins/input/shape/shapefile.hpp
@@ -34,9 +34,12 @@
 #include <mapnik/util/utf_conv_win.hpp>
 #include <mapnik/box2d.hpp>
 #ifdef SHAPE_MEMORY_MAPPED_FILE
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wshadow"
 #include <boost/interprocess/mapped_region.hpp>
-#include <mapnik/mapped_memory_cache.hpp>
 #include <boost/interprocess/streams/bufferstream.hpp>
+#pragma GCC diagnostic pop
+#include <mapnik/mapped_memory_cache.hpp>
 #endif
 #include <mapnik/util/noncopyable.hpp>
 
diff --git a/plugins/input/topojson/topojson_datasource.hpp b/plugins/input/topojson/topojson_datasource.hpp
index 829045028..8f5eb504d 100644
--- a/plugins/input/topojson/topojson_datasource.hpp
+++ b/plugins/input/topojson/topojson_datasource.hpp
@@ -40,6 +40,8 @@
 #pragma GCC diagnostic ignored "-Wunused-variable"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/geometry/geometries/geometries.hpp>
 #include <boost/geometry.hpp>
 #include <boost/version.hpp>
diff --git a/plugins/input/topojson/topojson_featureset.cpp b/plugins/input/topojson/topojson_featureset.cpp
index ed53932e8..0b319d2cb 100644
--- a/plugins/input/topojson/topojson_featureset.cpp
+++ b/plugins/input/topojson/topojson_featureset.cpp
@@ -132,7 +132,7 @@ struct feature_generator
         {
             index_type index = line.ring;
             index_type arc_index = index < 0 ? std::abs(index) - 1 : index;
-            if (arc_index < num_arcs_)
+            if (arc_index >= 0 && arc_index < static_cast<int>(num_arcs_))
             {            
                 auto const& arcs = topo_.arcs[arc_index];
                 double px = 0, py = 0;
@@ -168,7 +168,7 @@ struct feature_generator
             for (auto const& index : multi_line.rings)
             {
                 index_type arc_index = index < 0 ? std::abs(index) - 1 : index;
-                if (arc_index < num_arcs_)
+                if (arc_index >= 0 && arc_index < static_cast<int>(num_arcs_))
                 {
                     hit = true;
                     double px = 0, py = 0;
@@ -216,7 +216,7 @@ struct feature_generator
                     double px = 0, py = 0;
                     bool reverse = index < 0;
                     index_type arc_index = reverse ? std::abs(index) - 1 : index;
-                    if (arc_index < num_arcs_)
+                    if (arc_index >= 0 && arc_index < static_cast<int>(num_arcs_))
                     {
                         hit = true;
                         auto const& arcs = topo_.arcs[arc_index];
@@ -296,7 +296,7 @@ struct feature_generator
                         double px = 0, py = 0;
                         bool reverse = index < 0;
                         index_type arc_index = reverse ? std::abs(index) - 1 : index;
-                        if (arc_index < num_arcs_)
+                        if (arc_index >= 0 && arc_index < static_cast<int>(num_arcs_))
                         {
                             hit = true;
                             auto const& arcs = topo_.arcs[arc_index];
diff --git a/src/agg/agg_renderer.cpp b/src/agg/agg_renderer.cpp
index 67723d064..6b0f8bbb9 100644
--- a/src/agg/agg_renderer.cpp
+++ b/src/agg/agg_renderer.cpp
@@ -128,16 +128,16 @@ struct setup_agg_bg_visitor
     void operator() (marker_rgba8 const& marker)
     {
         mapnik::image_rgba8 const& bg_image = marker.get_data();
-        int w = bg_image.width();
-        int h = bg_image.height();
+        std::size_t w = bg_image.width();
+        std::size_t h = bg_image.height();
         if ( w > 0 && h > 0)
         {
             // repeat background-image both vertically and horizontally
-            unsigned x_steps = static_cast<unsigned>(std::ceil(common_.width_/double(w)));
-            unsigned y_steps = static_cast<unsigned>(std::ceil(common_.height_/double(h)));
-            for (unsigned x=0;x<x_steps;++x)
+            std::size_t x_steps = static_cast<std::size_t>(std::ceil(common_.width_/double(w)));
+            std::size_t y_steps = static_cast<std::size_t>(std::ceil(common_.height_/double(h)));
+            for (std::size_t x=0;x<x_steps;++x)
             {
-                for (unsigned y=0;y<y_steps;++y)
+                for (std::size_t y=0;y<y_steps;++y)
                 {
                     composite(pixmap_, bg_image, mode_, opacity_, x*w, y*h);
                 }
diff --git a/src/cairo/cairo_context.cpp b/src/cairo/cairo_context.cpp
index 2cc302c3d..57a82589e 100644
--- a/src/cairo/cairo_context.cpp
+++ b/src/cairo/cairo_context.cpp
@@ -486,9 +486,9 @@ void cairo_context::add_text(glyph_positions const& pos,
         matrix.y0 = 0;
         set_font_matrix(matrix);
         set_font_face(manager, glyph.face);
-        pixel_position pos = glyph_pos.pos + glyph.offset.rotate(glyph_pos.rot);
+        pixel_position new_pos = glyph_pos.pos + glyph.offset.rotate(glyph_pos.rot);
         set_color(glyph.format->fill, glyph.format->text_opacity);
-        show_glyph(glyph.glyph_index, pixel_position(sx + pos.x, sy - pos.y));
+        show_glyph(glyph.glyph_index, pixel_position(sx + new_pos.x, sy - new_pos.y));
     }
 
 }
diff --git a/src/cairo/cairo_renderer.cpp b/src/cairo/cairo_renderer.cpp
index b4293afac..24f3b54b7 100644
--- a/src/cairo/cairo_renderer.cpp
+++ b/src/cairo/cairo_renderer.cpp
@@ -110,16 +110,16 @@ struct setup_marker_visitor
     void operator() (marker_rgba8 const& marker)
     {
         mapnik::image_rgba8 const& bg_image = marker.get_data();
-        int w = bg_image.width();
-        int h = bg_image.height();
+        std::size_t w = bg_image.width();
+        std::size_t h = bg_image.height();
         if ( w > 0 && h > 0)
         {
             // repeat background-image both vertically and horizontally
-            unsigned x_steps = unsigned(std::ceil(common_.width_/double(w)));
-            unsigned y_steps = unsigned(std::ceil(common_.height_/double(h)));
-            for (unsigned x=0;x<x_steps;++x)
+            std::size_t x_steps = std::size_t(std::ceil(common_.width_/double(w)));
+            std::size_t y_steps = std::size_t(std::ceil(common_.height_/double(h)));
+            for (std::size_t x=0;x<x_steps;++x)
             {
-                for (unsigned y=0;y<y_steps;++y)
+                for (std::size_t y=0;y<y_steps;++y)
                 {
                     agg::trans_affine matrix = agg::trans_affine_translation(
                                                    x*w,
@@ -191,13 +191,13 @@ void cairo_renderer<T>::end_layer_processing(layer const&)
 }
 
 template <typename T>
-void cairo_renderer<T>::start_style_processing(feature_type_style const& st)
+void cairo_renderer<T>::start_style_processing(feature_type_style const&)
 {
     MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer:start style processing";
 }
 
 template <typename T>
-void cairo_renderer<T>::end_style_processing(feature_type_style const& st)
+void cairo_renderer<T>::end_style_processing(feature_type_style const&)
 {
     MAPNIK_LOG_DEBUG(cairo_renderer) << "cairo_renderer:end style processing";
 }
diff --git a/src/cairo/process_line_pattern_symbolizer.cpp b/src/cairo/process_line_pattern_symbolizer.cpp
index ff7dd018e..86f7c81c5 100644
--- a/src/cairo/process_line_pattern_symbolizer.cpp
+++ b/src/cairo/process_line_pattern_symbolizer.cpp
@@ -43,8 +43,8 @@ struct cairo_renderer_process_visitor_l
     cairo_renderer_process_visitor_l(renderer_common const& common,
                                    line_pattern_symbolizer const& sym,
                                    mapnik::feature_impl & feature,
-                                   unsigned & width,
-                                   unsigned & height)
+                                   std::size_t & width,
+                                   std::size_t & height)
         : common_(common),
           sym_(sym),
           feature_(feature),
@@ -81,8 +81,8 @@ struct cairo_renderer_process_visitor_l
     renderer_common const& common_;
     line_pattern_symbolizer const& sym_;
     mapnik::feature_impl & feature_;
-    unsigned & width_;
-    unsigned & height_;
+    std::size_t & width_;
+    std::size_t & height_;
 };
 
 template <typename T>
@@ -106,8 +106,8 @@ void cairo_renderer<T>::process(line_pattern_symbolizer const& sym,
 
     if (marker->is<mapnik::marker_null>()) return;
 
-    unsigned width = marker->width();
-    unsigned height = marker->height();
+    std::size_t width = marker->width();
+    std::size_t height = marker->height();
 
     cairo_save_restore guard(context_);
     context_.set_operator(comp_op);
diff --git a/src/cairo/process_markers_symbolizer.cpp b/src/cairo/process_markers_symbolizer.cpp
index 3cfb39496..a042a1ca1 100644
--- a/src/cairo/process_markers_symbolizer.cpp
+++ b/src/cairo/process_markers_symbolizer.cpp
@@ -59,7 +59,7 @@ struct vector_markers_dispatch_cairo  : public vector_markers_dispatch<Detector>
                                   double scale_factor,
                                   feature_impl & feature,
                                   mapnik::attributes const& vars,
-                                  bool snap_to_pixels,
+                                  bool /* snap_to_pixels */, // only used in agg renderer currently
                                   RendererContext const& renderer_context)
     : vector_markers_dispatch<Detector>(src, marker_trans, sym, detector, scale_factor, feature, vars),
         path_(path),
diff --git a/src/color.cpp b/src/color.cpp
index 5d25f3146..2a796e546 100644
--- a/src/color.cpp
+++ b/src/color.cpp
@@ -33,6 +33,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma.hpp>
 #include <boost/spirit/include/phoenix_statement.hpp>
 #include <boost/spirit/include/phoenix_core.hpp>
diff --git a/src/conversions.cpp b/src/conversions.cpp
index 094ac0e1e..ec6c8d17d 100644
--- a/src/conversions.cpp
+++ b/src/conversions.cpp
@@ -34,6 +34,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #ifdef MAPNIK_KARMA_TO_STRING
   #include <boost/spirit/include/karma.hpp>
diff --git a/src/grid/process_line_pattern_symbolizer.cpp b/src/grid/process_line_pattern_symbolizer.cpp
index 0b86c789b..56637fed2 100644
--- a/src/grid/process_line_pattern_symbolizer.cpp
+++ b/src/grid/process_line_pattern_symbolizer.cpp
@@ -82,7 +82,7 @@ void grid_renderer<T>::process(line_pattern_symbolizer const& sym,
 
     ras_ptr->reset();
 
-    int stroke_width = mark->width();
+    std::size_t stroke_width = mark->width();
 
     agg::trans_affine tr;
     auto transform = get_optional<transform_type>(sym, keys::geometry_transform);
diff --git a/src/group/group_layout_manager.cpp b/src/group/group_layout_manager.cpp
index 7c6f7b8c6..70d59524e 100644
--- a/src/group/group_layout_manager.cpp
+++ b/src/group/group_layout_manager.cpp
@@ -23,6 +23,7 @@
 // mapnik
 #include <mapnik/group/group_layout_manager.hpp>
 #include <mapnik/util/variant.hpp>
+#include <mapnik/safe_cast.hpp>
 
 // std
 #include <cmath>
@@ -85,7 +86,7 @@ struct process_layout
         }
 
         bound_box layout_box;
-        size_t middle_ifirst = (member_boxes_.size() - 1) >> 1;
+        int middle_ifirst = safe_cast<int>((member_boxes_.size() - 1) >> 1);
         int top_i = 0;
         int bottom_i = 0;
         if (middle_ifirst % 2 == 0)
@@ -102,8 +103,8 @@ struct process_layout
 
         while (bottom_i >= 0 && top_i >= 0 && top_i < static_cast<int>(member_offsets_.size()))
         {
-            layout_box.expand_to_include(make_horiz_pair(top_i, layout_box.miny() - y_margin, -1, x_margin, layout.get_max_difference()));
-            layout_box.expand_to_include(make_horiz_pair(bottom_i, layout_box.maxy() + y_margin, 1, x_margin, layout.get_max_difference()));
+            layout_box.expand_to_include(make_horiz_pair(static_cast<std::size_t>(top_i), layout_box.miny() - y_margin, -1, x_margin, layout.get_max_difference()));
+            layout_box.expand_to_include(make_horiz_pair(static_cast<std::size_t>(bottom_i), layout_box.maxy() + y_margin, 1, x_margin, layout.get_max_difference()));
             top_i -= 2;
             bottom_i += 2;
         }
diff --git a/src/image_copy.cpp b/src/image_copy.cpp
index ef220389e..55f501a74 100644
--- a/src/image_copy.cpp
+++ b/src/image_copy.cpp
@@ -50,10 +50,10 @@ struct visitor_image_copy
     template <typename T1>
     T0 operator() (T1 const& src)
     {
-        T0 dst(src.width(), src.height(), false);
-        for (unsigned y = 0; y < dst.height(); ++y)
+        T0 dst(safe_cast<int>(src.width()), safe_cast<int>(src.height()), false);
+        for (std::size_t y = 0; y < dst.height(); ++y)
         {
-            for (unsigned x = 0; x < dst.width(); ++x)
+            for (std::size_t x = 0; x < dst.width(); ++x)
             {
                 dst(x,y) = safe_cast<dst_type>(src(x,y));
             }
@@ -95,12 +95,12 @@ struct visitor_image_copy_so
     {
         double src_offset = src.get_offset();
         double src_scaling = src.get_scaling();
-        T0 dst(src.width(), src.height(), false);
+        T0 dst(safe_cast<int>(src.width()), safe_cast<int>(src.height()), false);
         dst.set_scaling(scaling_);
         dst.set_offset(offset_);
-        for (unsigned y = 0; y < dst.height(); ++y)
+        for (std::size_t y = 0; y < dst.height(); ++y)
         {
-            for (unsigned x = 0; x < dst.width(); ++x)
+            for (std::size_t x = 0; x < dst.width(); ++x)
             {
                 double scaled_src_val = (safe_cast<double>(src(x,y)) * src_scaling) + src_offset;
                 double dst_val = (scaled_src_val - offset_) / scaling_;
diff --git a/src/image_filter_types.cpp b/src/image_filter_types.cpp
index 22c474f86..cd5b7d3f1 100644
--- a/src/image_filter_types.cpp
+++ b/src/image_filter_types.cpp
@@ -30,6 +30,8 @@
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wmissing-field-initializers"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma.hpp>
 #pragma GCC diagnostic pop
 
diff --git a/src/image_util.cpp b/src/image_util.cpp
index 20db1aeda..d9ab7071a 100644
--- a/src/image_util.cpp
+++ b/src/image_util.cpp
@@ -489,7 +489,7 @@ struct premultiply_visitor
     {
         if (!data.get_premultiplied())
         {
-            agg::rendering_buffer buffer(data.bytes(),data.width(),data.height(),data.row_size());
+            agg::rendering_buffer buffer(data.bytes(),safe_cast<unsigned>(data.width()),safe_cast<unsigned>(data.height()),safe_cast<int>(data.row_size()));
             agg::pixfmt_rgba32 pixf(buffer);
             pixf.premultiply();
             data.set_premultiplied(true);
@@ -511,7 +511,7 @@ struct demultiply_visitor
     {
         if (data.get_premultiplied())
         {
-            agg::rendering_buffer buffer(data.bytes(),data.width(),data.height(),data.row_size());
+            agg::rendering_buffer buffer(data.bytes(),safe_cast<unsigned>(data.width()),safe_cast<unsigned>(data.height()),safe_cast<int>(data.row_size()));
             agg::pixfmt_rgba32_pre pixf(buffer);
             pixf.demultiply();
             data.set_premultiplied(false);
@@ -641,12 +641,12 @@ struct visitor_apply_opacity
             for (std::size_t x = 0; x < data.width(); ++x)
             {
                 pixel_type rgba = row_to[x];
-                pixel_type a = static_cast<pixel_type>(((rgba >> 24) & 0xff) * opacity_);
+                pixel_type a = static_cast<pixel_type>(((rgba >> 24u) & 0xff) * opacity_);
                 pixel_type r = rgba & 0xff;
-                pixel_type g = (rgba >> 8 ) & 0xff;
-                pixel_type b = (rgba >> 16) & 0xff;
+                pixel_type g = (rgba >> 8u ) & 0xff;
+                pixel_type b = (rgba >> 16u) & 0xff;
 
-                row_to[x] = (a << 24)| (b << 16) |  (g << 8) | (r) ;
+                row_to[x] = (a << 24u) | (b << 16u) |  (g << 8u) | (r) ;
             }
         }
     }
@@ -713,13 +713,13 @@ struct visitor_set_grayscale_to_alpha
             {
                 pixel_type rgba = row_from[x];
                 pixel_type r = rgba & 0xff;
-                pixel_type g = (rgba >> 8 ) & 0xff;
-                pixel_type b = (rgba >> 16) & 0xff;
+                pixel_type g = (rgba >> 8u) & 0xff;
+                pixel_type b = (rgba >> 16u) & 0xff;
 
                 // magic numbers for grayscale
                 pixel_type a = static_cast<pixel_type>(std::ceil((r * .3) + (g * .59) + (b * .11)));
 
-                row_from[x] = (a << 24)| (255 << 16) |  (255 << 8) | (255) ;
+                row_from[x] = (a << 24u) | (255 << 16u) |  (255 << 8u) | (255u) ;
             }
         }
     }
@@ -752,7 +752,10 @@ struct visitor_set_grayscale_to_alpha_c
                 // magic numbers for grayscale
                 pixel_type a = static_cast<pixel_type>(std::ceil((r * .3) + (g * .59) + (b * .11)));
 
-                row_from[x] = (a << 24)| (c_.blue() << 16) |  (c_.green() << 8) | (c_.red()) ;
+                row_from[x] = static_cast<unsigned>(a << 24u) |
+                              static_cast<unsigned>(c_.blue() << 16u) | 
+                              static_cast<unsigned>(c_.green() << 8u) |
+                              static_cast<unsigned>(c_.red() );
             }
         }
     }
@@ -1217,9 +1220,10 @@ struct visitor_composite_pixel
         if (mapnik::check_bounds(data, x_, y_))
         {
             image_rgba8::pixel_type rgba = data(x_,y_);
-            value_type ca = static_cast<unsigned>(((c_ >> 24) & 0xff) * opacity_);
-            value_type cb = (c_ >> 16 ) & 0xff;
-            value_type cg = (c_ >> 8) & 0xff;
+            // TODO use std::round for consistent rounding
+            value_type ca = safe_cast<value_type>(((c_ >> 24u) & 0xff) * opacity_);
+            value_type cb = (c_ >> 16u) & 0xff;
+            value_type cg = (c_ >> 8u) & 0xff;
             value_type cr = (c_ & 0xff);
             blender_type::blend_pix(comp_op_, reinterpret_cast<value_type*>(&rgba), cr, cg, cb, ca, cover_);
             data(x_,y_) = rgba;
@@ -1227,7 +1231,7 @@ struct visitor_composite_pixel
     }
 
     template <typename T>
-    void operator() (T & data) const
+    void operator() (T &) const
     {
         throw std::runtime_error("Composite pixel is not supported for this data type");
     }
@@ -1237,7 +1241,7 @@ private:
     composite_mode_e comp_op_;
     std::size_t const x_;
     std::size_t const y_;
-    int const c_;
+    unsigned const c_;
     unsigned const cover_;
 
 };
@@ -2082,7 +2086,7 @@ struct visitor_view_to_stream
         for (std::size_t i=0;i<view.height();i++)
         {
             os_.write(reinterpret_cast<const char*>(view.get_row(i)),
-                      view.row_size());
+                      safe_cast<std::streamsize>(view.row_size()));
         }
     }
 
@@ -2251,11 +2255,11 @@ MAPNIK_DECL std::size_t compare<image_rgba8>(image_rgba8 const& im1, image_rgba8
                 unsigned rgba = row_from[x];
                 unsigned rgba2 = row_from2[x];
                 unsigned r = rgba & 0xff;
-                unsigned g = (rgba >> 8 ) & 0xff;
-                unsigned b = (rgba >> 16) & 0xff;
+                unsigned g = (rgba >> 8u) & 0xff;
+                unsigned b = (rgba >> 16u) & 0xff;
                 unsigned r2 = rgba2 & 0xff;
-                unsigned g2 = (rgba2 >> 8 ) & 0xff;
-                unsigned b2 = (rgba2 >> 16) & 0xff;
+                unsigned g2 = (rgba2 >> 8u) & 0xff;
+                unsigned b2 = (rgba2 >> 16u) & 0xff;
                 if (std::abs(static_cast<int>(r - r2)) > static_cast<int>(threshold) ||
                     std::abs(static_cast<int>(g - g2)) > static_cast<int>(threshold) ||
                     std::abs(static_cast<int>(b - b2)) > static_cast<int>(threshold)) {
@@ -2263,8 +2267,8 @@ MAPNIK_DECL std::size_t compare<image_rgba8>(image_rgba8 const& im1, image_rgba8
                     continue;
                 }
                 if (alpha) {
-                    unsigned a = (rgba >> 24) & 0xff;
-                    unsigned a2 = (rgba2 >> 24) & 0xff;
+                    unsigned a = (rgba >> 24u) & 0xff;
+                    unsigned a2 = (rgba2 >> 24u) & 0xff;
                     if (std::abs(static_cast<int>(a - a2)) > static_cast<int>(threshold)) {
                         ++difference;
                         continue;
@@ -2289,11 +2293,11 @@ MAPNIK_DECL std::size_t compare<image_rgba8>(image_rgba8 const& im1, image_rgba8
             unsigned rgba = row_from[x];
             unsigned rgba2 = row_from2[x];
             unsigned r = rgba & 0xff;
-            unsigned g = (rgba >> 8 ) & 0xff;
-            unsigned b = (rgba >> 16) & 0xff;
+            unsigned g = (rgba >> 8u) & 0xff;
+            unsigned b = (rgba >> 16u) & 0xff;
             unsigned r2 = rgba2 & 0xff;
-            unsigned g2 = (rgba2 >> 8 ) & 0xff;
-            unsigned b2 = (rgba2 >> 16) & 0xff;
+            unsigned g2 = (rgba2 >> 8u) & 0xff;
+            unsigned b2 = (rgba2 >> 16u) & 0xff;
             if (std::abs(static_cast<int>(r - r2)) > static_cast<int>(threshold) ||
                 std::abs(static_cast<int>(g - g2)) > static_cast<int>(threshold) ||
                 std::abs(static_cast<int>(b - b2)) > static_cast<int>(threshold)) {
@@ -2301,8 +2305,8 @@ MAPNIK_DECL std::size_t compare<image_rgba8>(image_rgba8 const& im1, image_rgba8
                 continue;
             }
             if (alpha) {
-                unsigned a = (rgba >> 24) & 0xff;
-                unsigned a2 = (rgba2 >> 24) & 0xff;
+                unsigned a = (rgba >> 24u) & 0xff;
+                unsigned a2 = (rgba2 >> 24u) & 0xff;
                 if (std::abs(static_cast<int>(a - a2)) > static_cast<int>(threshold)) {
                     ++difference;
                     continue;
diff --git a/src/image_view_any.cpp b/src/image_view_any.cpp
index 8bf89b45b..b05e539cb 100644
--- a/src/image_view_any.cpp
+++ b/src/image_view_any.cpp
@@ -47,7 +47,7 @@ struct get_view_height_visitor
 struct get_view_size_visitor
 {
     template <typename T>
-    unsigned operator()(T const& data) const
+    std::size_t operator()(T const& data) const
     {
         return data.size();
     }
@@ -65,7 +65,7 @@ struct get_view_dtype_visitor
 struct get_view_row_size_visitor
 {
     template <typename T>
-    unsigned operator()(T const& data) const
+    std::size_t operator()(T const& data) const
     {
         return data.row_size();
     }
diff --git a/src/load_map.cpp b/src/load_map.cpp
index fc38407ab..419b8bc39 100644
--- a/src/load_map.cpp
+++ b/src/load_map.cpp
@@ -80,7 +80,7 @@ using boost::optional;
 
 constexpr unsigned name2int(const char *str, int off = 0)
 {
-    return !str[off] ? 5381 : (name2int(str, off+1)*33) ^ str[off];
+    return !str[off] ? 5381 : (name2int(str, off+1)*33) ^ static_cast<unsigned>(str[off]);
 }
 
 class map_parser : util::noncopyable
@@ -147,8 +147,7 @@ private:
 
 void load_map(Map & map, std::string const& filename, bool strict, std::string base_path)
 {
-    // TODO - use xml encoding?
-    xml_tree tree("utf8");
+    xml_tree tree;
     tree.set_filename(filename);
     read_xml(filename, tree.root());
     map_parser parser(map, strict, filename);
@@ -157,8 +156,7 @@ void load_map(Map & map, std::string const& filename, bool strict, std::string b
 
 void load_map_string(Map & map, std::string const& str, bool strict, std::string base_path)
 {
-    // TODO - use xml encoding?
-    xml_tree tree("utf8");
+    xml_tree tree;
     if (!base_path.empty())
     {
         read_xml_string(str, tree.root(), base_path); // accept base_path passed into function
@@ -237,7 +235,7 @@ void map_parser::parse_map(Map & map, xml_node const& node, std::string const& b
             }
             map.set_srs(srs);
 
-            optional<unsigned> buffer_size = map_node.get_opt_attr<unsigned>("buffer-size");
+            optional<int> buffer_size = map_node.get_opt_attr<int>("buffer-size");
             if (buffer_size)
             {
                 map.set_buffer_size(*buffer_size);
@@ -648,7 +646,7 @@ void map_parser::parse_layer(Map & map, xml_node const& node)
             lyr.set_group_by(* group_by);
         }
 
-        optional<unsigned> buffer_size = node.get_opt_attr<unsigned>("buffer-size");
+        optional<int> buffer_size = node.get_opt_attr<int>("buffer-size");
         if (buffer_size)
         {
             lyr.set_buffer_size(*buffer_size);
diff --git a/src/marker_cache.cpp b/src/marker_cache.cpp
index e7c46a259..4e15caf3e 100644
--- a/src/marker_cache.cpp
+++ b/src/marker_cache.cpp
@@ -126,13 +126,13 @@ struct visitor_create_marker
         return mapnik::marker(mapnik::marker_rgba8(data));
     }
 
-    marker operator() (image_null & data)
+    marker operator() (image_null &)
     {
         throw std::runtime_error("Can not make marker from null image data type");
     }
 
     template <typename T>
-    marker operator() (T & data)
+    marker operator() (T &)
     {
         throw std::runtime_error("Can not make marker from this data type");
     }
diff --git a/src/renderer_common.cpp b/src/renderer_common.cpp
index ecba13655..f6b2bb77d 100644
--- a/src/renderer_common.cpp
+++ b/src/renderer_common.cpp
@@ -25,6 +25,7 @@
 #include <mapnik/map.hpp>
 #include <mapnik/request.hpp>
 #include <mapnik/attribute.hpp>
+#include <mapnik/safe_cast.hpp>
 
 namespace mapnik {
 
diff --git a/src/save_map.cpp b/src/save_map.cpp
index eea8cda2a..c9f681130 100644
--- a/src/save_map.cpp
+++ b/src/save_map.cpp
@@ -465,13 +465,12 @@ void serialize_fontset( ptree & map_node, std::string const& name, font_set cons
 
     set_attr(fontset_node, "name", name);
 
-    for (auto const& name : fontset.get_face_names())
+    for (auto const& face_name : fontset.get_face_names())
     {
         ptree & font_node = fontset_node.push_back(
             ptree::value_type("Font", ptree()))->second;
-        set_attr(font_node, "face-name", name);
+        set_attr(font_node, "face-name", face_name);
     }
-
 }
 
 void serialize_datasource( ptree & layer_node, datasource_ptr datasource)
@@ -507,63 +506,63 @@ void serialize_parameters( ptree & map_node, mapnik::parameters const& params)
     }
 }
 
-void serialize_layer( ptree & map_node, const layer & layer, bool explicit_defaults )
+void serialize_layer( ptree & map_node, layer const& lyr, bool explicit_defaults )
 {
     ptree & layer_node = map_node.push_back(
         ptree::value_type("Layer", ptree()))->second;
 
-    if ( layer.name() != "" )
+    if ( lyr.name() != "" )
     {
-        set_attr( layer_node, "name", layer.name() );
+        set_attr( layer_node, "name", lyr.name() );
     }
 
-    if ( layer.srs() != "" )
+    if ( lyr.srs() != "" )
     {
-        set_attr( layer_node, "srs", layer.srs() );
+        set_attr( layer_node, "srs", lyr.srs() );
     }
 
-    if ( !layer.active() || explicit_defaults )
+    if ( !lyr.active() || explicit_defaults )
     {
-        set_attr/*<bool>*/( layer_node, "status", layer.active() );
+        set_attr/*<bool>*/( layer_node, "status", lyr.active() );
     }
 
-    if ( layer.clear_label_cache() || explicit_defaults )
+    if ( lyr.clear_label_cache() || explicit_defaults )
     {
-        set_attr/*<bool>*/( layer_node, "clear-label-cache", layer.clear_label_cache() );
+        set_attr/*<bool>*/( layer_node, "clear-label-cache", lyr.clear_label_cache() );
     }
 
-    if ( layer.minimum_scale_denominator() )
+    if ( lyr.minimum_scale_denominator() != 0 || explicit_defaults )
     {
-        set_attr( layer_node, "minimum_scale_denominator", layer.minimum_scale_denominator() );
+        set_attr( layer_node, "minimum_scale_denominator", lyr.minimum_scale_denominator() );
     }
 
-    if ( layer.maximum_scale_denominator() != std::numeric_limits<double>::max() )
+    if ( lyr.maximum_scale_denominator() != std::numeric_limits<double>::max() || explicit_defaults )
     {
-        set_attr( layer_node, "maximum_scale_denominator", layer.maximum_scale_denominator() );
+        set_attr( layer_node, "maximum_scale_denominator", lyr.maximum_scale_denominator() );
     }
 
-    if ( layer.queryable() || explicit_defaults )
+    if ( lyr.queryable() || explicit_defaults )
     {
-        set_attr( layer_node, "queryable", layer.queryable() );
+        set_attr( layer_node, "queryable", lyr.queryable() );
     }
 
-    if ( layer.cache_features() || explicit_defaults )
+    if ( lyr.cache_features() || explicit_defaults )
     {
-        set_attr/*<bool>*/( layer_node, "cache-features", layer.cache_features() );
+        set_attr/*<bool>*/( layer_node, "cache-features", lyr.cache_features() );
     }
 
-    if ( layer.group_by() != "" || explicit_defaults )
+    if ( lyr.group_by() != "" || explicit_defaults )
     {
-        set_attr( layer_node, "group-by", layer.group_by() );
+        set_attr( layer_node, "group-by", lyr.group_by() );
     }
 
-    boost::optional<int> const& buffer_size = layer.buffer_size();
+    boost::optional<int> const& buffer_size = lyr.buffer_size();
     if ( buffer_size || explicit_defaults)
     {
         set_attr( layer_node, "buffer-size", *buffer_size );
     }
 
-    optional<box2d<double> > const& maximum_extent = layer.maximum_extent();
+    optional<box2d<double> > const& maximum_extent = lyr.maximum_extent();
     if ( maximum_extent)
     {
         std::ostringstream s;
@@ -573,7 +572,7 @@ void serialize_layer( ptree & map_node, const layer & layer, bool explicit_defau
         set_attr( layer_node, "maximum-extent", s.str() );
     }
 
-    for (auto const& name : layer.styles())
+    for (auto const& name : lyr.styles())
     {
         boost::property_tree::ptree & style_node = layer_node.push_back(
             boost::property_tree::ptree::value_type("StyleName",
@@ -581,7 +580,7 @@ void serialize_layer( ptree & map_node, const layer & layer, bool explicit_defau
         style_node.put_value(name);
     }
 
-    datasource_ptr datasource = layer.datasource();
+    datasource_ptr datasource = lyr.datasource();
     if ( datasource )
     {
         serialize_datasource( layer_node, datasource );
diff --git a/src/svg/output/svg_generator.cpp b/src/svg/output/svg_generator.cpp
index 5c48702d4..9bc3e7285 100644
--- a/src/svg/output/svg_generator.cpp
+++ b/src/svg/output/svg_generator.cpp
@@ -32,6 +32,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wshadow"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/karma.hpp>
 #pragma GCC diagnostic pop
 
diff --git a/src/svg/svg_parser.cpp b/src/svg/svg_parser.cpp
index a6fa1ee5b..7794fa5d3 100644
--- a/src/svg/svg_parser.cpp
+++ b/src/svg/svg_parser.cpp
@@ -25,6 +25,7 @@
 #include <mapnik/svg/svg_parser.hpp>
 #include <mapnik/svg/svg_path_parser.hpp>
 #include <mapnik/config_error.hpp>
+#include <mapnik/safe_cast.hpp>
 
 #include "agg_ellipse.h"
 #include "agg_rounded_rect.h"
@@ -34,6 +35,7 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix_core.hpp>
 #include <boost/spirit/include/phoenix_operator.hpp>
@@ -1075,7 +1077,7 @@ void svg_parser::parse(std::string const& filename)
 
 void svg_parser::parse_from_string(std::string const& svg)
 {
-    xmlTextReaderPtr reader = xmlReaderForMemory(svg.c_str(),svg.size(),nullptr,nullptr,
+    xmlTextReaderPtr reader = xmlReaderForMemory(svg.c_str(),safe_cast<int>(svg.size()),nullptr,nullptr,
         (XML_PARSE_NOBLANKS | XML_PARSE_NOCDATA | XML_PARSE_NOERROR | XML_PARSE_NOWARNING));
     if (reader == nullptr)
     {
diff --git a/src/text/formatting/text.cpp b/src/text/formatting/text.cpp
index 8247bd26a..6446f2c31 100644
--- a/src/text/formatting/text.cpp
+++ b/src/text/formatting/text.cpp
@@ -46,7 +46,7 @@ void text_node::to_xml(ptree & xml) const
     new_node.put_value(to_expression_string(*text_));
 }
 
-node_ptr text_node::from_xml(xml_node const& xml, fontset_map const& fontsets)
+node_ptr text_node::from_xml(xml_node const& xml, fontset_map const&)
 {
     return std::make_shared<text_node>(xml.get_value<expression_ptr>());
 }
diff --git a/src/text/placements/dummy.cpp b/src/text/placements/dummy.cpp
index 569b5df48..cb398a410 100644
--- a/src/text/placements/dummy.cpp
+++ b/src/text/placements/dummy.cpp
@@ -33,7 +33,7 @@ bool text_placement_info_dummy::next() const
 }
 
 text_placement_info_ptr text_placements_dummy::get_placement_info(
-    double scale_factor, feature_impl const& feature, attributes const& vars) const
+    double scale_factor, feature_impl const&, attributes const&) const
 {
     return std::make_shared<text_placement_info_dummy>(this, scale_factor);
 }
diff --git a/src/text/placements/list.cpp b/src/text/placements/list.cpp
index 1c40b68cf..ffbbac846 100644
--- a/src/text/placements/list.cpp
+++ b/src/text/placements/list.cpp
@@ -65,7 +65,7 @@ text_symbolizer_properties & text_placements_list::get(unsigned i)
 }
 
 
-text_placement_info_ptr text_placements_list::get_placement_info(double scale_factor, feature_impl const& feature, attributes const& vars) const
+text_placement_info_ptr text_placements_list::get_placement_info(double scale_factor, feature_impl const&, attributes const&) const
 {
     return std::make_shared<text_placement_info_list>(this, scale_factor);
 }
@@ -83,7 +83,7 @@ void text_placements_list::add_expressions(expression_set & output) const
     }
 }
 
-unsigned text_placements_list::size() const
+std::size_t text_placements_list::size() const
 {
     return list_.size();
 }
diff --git a/src/text/placements/simple.cpp b/src/text/placements/simple.cpp
index 693b0bacd..4918dac1d 100644
--- a/src/text/placements/simple.cpp
+++ b/src/text/placements/simple.cpp
@@ -35,6 +35,8 @@
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-local-typedef"
 #pragma GCC diagnostic ignored "-Wmissing-field-initializers"
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#pragma GCC diagnostic ignored "-Wconversion"
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/phoenix_core.hpp>
 #include <boost/spirit/include/phoenix_stl.hpp>
@@ -185,7 +187,7 @@ namespace detail {
         }
 
         template <typename T>
-        std::string operator() (T const& val) const
+        std::string operator() (T const&) const
         {
             return "";
         }
diff --git a/src/text/symbolizer_helpers.cpp b/src/text/symbolizer_helpers.cpp
index 9890189ff..4771b0eca 100644
--- a/src/text/symbolizer_helpers.cpp
+++ b/src/text/symbolizer_helpers.cpp
@@ -342,7 +342,7 @@ public:
     }
 
     template <typename T>
-    bool operator()(T const & geo) const
+    bool operator()(T const&) const
     {
         return false;
     }
diff --git a/src/xml_tree.cpp b/src/xml_tree.cpp
index 410a2bcf0..7ec11ca6b 100644
--- a/src/xml_tree.cpp
+++ b/src/xml_tree.cpp
@@ -68,6 +68,7 @@ struct name_trait
 DEFINE_NAME_TRAIT( double, "double")
 DEFINE_NAME_TRAIT( float, "float")
 DEFINE_NAME_TRAIT( unsigned, "unsigned")
+DEFINE_NAME_TRAIT( int, "int")
 DEFINE_NAME_TRAIT( boolean_type, "boolean_type")
 #ifdef BIGINT
 DEFINE_NAME_TRAIT( mapnik::value_integer, "long long" )
@@ -98,7 +99,7 @@ struct name_trait< mapnik::enumeration<ENUM, MAX> >
     }
 };
 
-xml_tree::xml_tree(std::string const& encoding)
+xml_tree::xml_tree()
     : node_(*this, "<root>"),
       file_()
 {
@@ -413,6 +414,7 @@ std::string xml_node::line_to_string() const
 
 compile_get_opt_attr(boolean_type);
 compile_get_opt_attr(std::string);
+compile_get_opt_attr(int);
 compile_get_opt_attr(unsigned);
 compile_get_opt_attr(mapnik::value_integer);
 compile_get_opt_attr(float);
diff --git a/test/unit/serialization/xml_parser_trim.cpp b/test/unit/serialization/xml_parser_trim.cpp
index ffc5ca8be..f79c75502 100644
--- a/test/unit/serialization/xml_parser_trim.cpp
+++ b/test/unit/serialization/xml_parser_trim.cpp
@@ -21,7 +21,7 @@ TEST_CASE("xml parser") {
                           "  </Layer>"
                           "</Map>");
 
-    mapnik::xml_tree tree("utf8");
+    mapnik::xml_tree tree;
     tree.set_filename("xml_datasource_parameter_trim.cpp");
     REQUIRE_NOTHROW(read_xml_string(xml, tree.root(), ""));