diff --git a/bindings/python/python_grid_utils.cpp b/bindings/python/python_grid_utils.cpp
index 2d90dec85..9913d9724 100644
--- a/bindings/python/python_grid_utils.cpp
+++ b/bindings/python/python_grid_utils.cpp
@@ -50,7 +50,7 @@ void grid2utf(T const& grid_type,
                      std::vector<typename T::lookup_type>& key_order)
 {
     using keys_type = std::map< typename T::lookup_type, typename T::value_type>;
-    using keys_iterator = typename keys_type::const_iterator;
+    using keys_iterator = typename keys_type::iterator;
 
     typename T::data_type const& data = grid_type.data();
     typename T::feature_key_type const& feature_keys = grid_type.get_feature_keys();
@@ -114,7 +114,7 @@ void grid2utf(T const& grid_type,
                      unsigned int resolution)
 {
     using keys_type = std::map< typename T::lookup_type, typename T::value_type>;
-    using keys_iterator = typename keys_type::const_iterator;
+    using keys_iterator = typename keys_type::iterator;
 
     typename T::feature_key_type const& feature_keys = grid_type.get_feature_keys();
     typename T::feature_key_type::const_iterator feature_pos;
@@ -177,7 +177,7 @@ void grid2utf2(T const& grid_type,
                       unsigned int resolution)
 {
     using keys_type = std::map< typename T::lookup_type, typename T::value_type>;
-    using keys_iterator = typename keys_type::const_iterator;
+    using keys_iterator = typename keys_type::iterator;
 
     typename T::data_type const& data = grid_type.data();
     typename T::feature_key_type const& feature_keys = grid_type.get_feature_keys();