diff --git a/include/mapnik/json/geometry_generator_grammar.hpp b/include/mapnik/json/geometry_generator_grammar.hpp
index c4803d8ab..2c21bab97 100644
--- a/include/mapnik/json/geometry_generator_grammar.hpp
+++ b/include/mapnik/json/geometry_generator_grammar.hpp
@@ -268,7 +268,7 @@ struct geometry_generator_grammar :
             ;
 
         polygon_coord %= ( &uint_(mapnik::SEG_MOVETO) << eps[_r1 += 1]
-                           << karma::string[ if_ (_r1 > 1) [_1 = "],["]
+                           << karma::string[ if_ (_r1 > 1u) [_1 = "],["]
                                              .else_[_1 = '[' ]]
                            |
                            &uint_(mapnik::SEG_LINETO)
@@ -340,9 +340,9 @@ struct multi_geometry_generator_grammar :
         geometry = ( &bool_(true)[_1 = not_empty_(_val)] << lit("{\"type\":")
                      << geometry_types[_1 = phoenix::at_c<0>(_a)][_a = multi_type_(_val)]
                      << lit(",\"coordinates\":")
-                     << karma::string[ phoenix::if_ (phoenix::at_c<0>(_a) > 3) [_1 = '['].else_[_1 = ""]]
+                     << karma::string[ phoenix::if_ (phoenix::at_c<0>(_a) > 3u) [_1 = '['].else_[_1 = ""]]
                      << coordinates
-                     << karma::string[ phoenix::if_ (phoenix::at_c<0>(_a) > 3) [_1 = ']'].else_[_1 = ""]]
+                     << karma::string[ phoenix::if_ (phoenix::at_c<0>(_a) > 3u) [_1 = ']'].else_[_1 = ""]]
                      << lit('}')) | lit("null")
             ;
 
diff --git a/include/mapnik/util/geometry_svg_generator.hpp b/include/mapnik/util/geometry_svg_generator.hpp
index 9fec4ae65..210a376bf 100644
--- a/include/mapnik/util/geometry_svg_generator.hpp
+++ b/include/mapnik/util/geometry_svg_generator.hpp
@@ -194,7 +194,7 @@ namespace mapnik { namespace util {
                 ;
 
             svg_path %= ((&uint_(mapnik::SEG_MOVETO) << lit('M')
-                          | &uint_(mapnik::SEG_LINETO) [_a +=1] << karma::string [if_(_a == 1) [_1 = "L" ].else_[_1 =""]])
+                          | &uint_(mapnik::SEG_LINETO) [_a +=1] << karma::string [if_(_a == 1u) [_1 = "L" ].else_[_1 =""]])
                          << lit(' ') << coordinate << lit(' ') << coordinate) % lit(' ')
                 ;
 
diff --git a/src/wkt/wkt_generator.cpp b/src/wkt/wkt_generator.cpp
index 16f81bfe5..cb1a11874 100644
--- a/src/wkt/wkt_generator.cpp
+++ b/src/wkt/wkt_generator.cpp
@@ -97,7 +97,7 @@ wkt_generator<OutputIterator, Geometry>::wkt_generator(bool single)
 
     polygon_coord %= ( &uint_(mapnik::SEG_MOVETO)
                        << eps[_r1 += 1][_a  = _x(_val)][ _b = _y(_val)]
-                       << string[ if_ (_r1 > 1) [_1 = "),("]
+                       << string[ if_ (_r1 > 1u) [_1 = "),("]
                                   .else_[_1 = "("]]
                        |
                        &uint_(mapnik::SEG_LINETO)