diff --git a/include/mapnik/global.hpp b/include/mapnik/global.hpp
index 22efed271..f4e200da8 100644
--- a/include/mapnik/global.hpp
+++ b/include/mapnik/global.hpp
@@ -2,7 +2,7 @@
  *
  * This file is part of Mapnik (c++ mapping toolkit)
  *
- * Copyright (C) 2011 Artem Pavlenko
+ * Copyright (C) 2013 Artem Pavlenko
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -29,6 +29,7 @@
 
 // stl
 #include <cstring>
+#include <cmath>
 
 namespace mapnik
 {