text: // Boost.Geometry (aka GGL, Generic Geometry Library)
  
  // Copyright (c) 2007-2011 Barend Gehrels, Amsterdam, the Netherlands.
  
  // Use, modification and distribution is subject to the Boost Software License,
  // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  // http://www.boost.org/LICENSE_1_0.txt)
  
  #ifndef BOOST_GEOMETRY_ALGORITHMS_SYM_DIFFERENCE_HPP
  #define BOOST_GEOMETRY_ALGORITHMS_SYM_DIFFERENCE_HPP
  
  #include <algorithm>
  
  
  #include <boost/geometry/algorithms/intersection.hpp>
  
  
  namespace boost { namespace geometry
  {
  
  #ifndef DOXYGEN_NO_DETAIL
  namespace detail { namespace sym_difference
  {
  
  
  
  /*!
  \brief \brief_calc2{symmetric difference}  \brief_strategy
  \ingroup sym_difference
  \details \details_calc2{symmetric difference, spatial set theoretic symmetric difference (XOR)}
      \brief_strategy. \details_insert{sym_difference}
  \tparam GeometryOut output geometry type, must be specified
  \tparam Geometry1 \tparam_geometry
  \tparam Geometry2 \tparam_geometry
  \tparam Strategy \tparam_strategy_overlay
  \param geometry1 \param_geometry
  \param geometry2 \param_geometry
  \param out \param_out{difference}
  \param strategy \param_strategy{difference}
  \return \return_out
  
  \qbk{distinguish,with strategy}
  */
  template
  <
      typename GeometryOut,
      typename Geometry1,
      typename Geometry2,
      typename OutputIterator,
      typename Strategy
  >
  inline OutputIterator sym_difference_insert(Geometry1 const& geometry1,
              Geometry2 const& geometry2, OutputIterator out,
              Strategy const& strategy)
  {
      concept::check<Geometry1 const>();
      concept::check<Geometry2 const>();
      concept::check<GeometryOut>();
  
      out = detail::intersection::insert<GeometryOut, true, overlay_difference>(
              geometry1, geometry2, out, strategy);
      out = detail::intersection::insert<GeometryOut, true, overlay_difference>(
              geometry2, geometry1, out, strategy);
      return out;
  }
  
  
  /*!
  \brief \brief_calc2{symmetric difference}
  \ingroup sym_difference
  \details \details_calc2{symmetric difference, spatial set theoretic symmetric difference (XOR)}
      \details_insert{sym_difference}
  \tparam GeometryOut output geometry type, must be specified
  \tparam Geometry1 \tparam_geometry
  \tparam Geometry2 \tparam_geometry
  \param geometry1 \param_geometry
  \param geometry2 \param_geometry
  \param out \param_out{difference}
  \return \return_out
  
  */
  template
  <
      typename GeometryOut,
      typename Geometry1,
      typename Geometry2,
      typename OutputIterator
  >
  inline OutputIterator sym_difference_insert(Geometry1 const& geometry1,
              Geometry2 const& geometry2, OutputIterator out)
  {
      concept::check<Geometry1 const>();
      concept::check<Geometry2 const>();
      concept::check<GeometryOut>();
  
      typedef strategy_intersection
          <
              typename cs_tag<GeometryOut>::type,
              Geometry1,
              Geometry2,
              typename geometry::point_type<GeometryOut>::type
          > strategy_type;
  
      return sym_difference_insert<GeometryOut>(geometry1, geometry2, out, strategy_type());
  }
  
  }} // namespace detail::sym_difference
  #endif // DOXYGEN_NO_DETAIL
  
  
  /*!
  \brief \brief_calc2{symmetric difference}
  \ingroup sym_difference
  \details \details_calc2{symmetric difference, spatial set theoretic symmetric difference (XOR)}.
  \tparam Geometry1 \tparam_geometry
  \tparam Geometry2 \tparam_geometry
  \tparam Collection output collection, either a multi-geometry,
      or a std::vector<Geometry> / std::deque<Geometry> etc
  \param geometry1 \param_geometry
  \param geometry2 \param_geometry
  \param output_collection the output collection
  
  \qbk{[include reference/algorithms/sym_difference.qbk]}
  */
  template
  <
      typename Geometry1,
      typename Geometry2,
      typename Collection
  >
  inline void sym_difference(Geometry1 const& geometry1,
              Geometry2 const& geometry2, Collection& output_collection)
  {
      concept::check<Geometry1 const>();
      concept::check<Geometry2 const>();
  
      typedef typename boost::range_value<Collection>::type geometry_out;
      concept::check<geometry_out>();
  
      detail::sym_difference::sym_difference_insert<geometry_out>(
              geometry1, geometry2,
              std::back_inserter(output_collection));
  }
  
  
  }} // namespace boost::geometry
  
  
  #endif // BOOST_GEOMETRY_ALGORITHMS_SYM_DIFFERENCE_HPP
  