376 lines
11 KiB
C++
376 lines
11 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
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// Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
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// Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
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// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
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// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_GEOMETRY_ALGORITHMS_SIMPLIFY_HPP
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#define BOOST_GEOMETRY_ALGORITHMS_SIMPLIFY_HPP
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#include <cstddef>
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#include <boost/range.hpp>
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#include <boost/typeof/typeof.hpp>
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#include <boost/geometry/core/cs.hpp>
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#include <boost/geometry/core/closure.hpp>
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#include <boost/geometry/core/ring_type.hpp>
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#include <boost/geometry/core/exterior_ring.hpp>
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#include <boost/geometry/core/interior_rings.hpp>
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#include <boost/geometry/core/mutable_range.hpp>
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#include <boost/geometry/geometries/concepts/check.hpp>
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#include <boost/geometry/strategies/agnostic/simplify_douglas_peucker.hpp>
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#include <boost/geometry/strategies/concepts/simplify_concept.hpp>
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#include <boost/geometry/algorithms/clear.hpp>
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#include <boost/geometry/algorithms/convert.hpp>
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#include <boost/geometry/algorithms/not_implemented.hpp>
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#include <boost/geometry/algorithms/num_interior_rings.hpp>
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namespace boost { namespace geometry
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{
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#ifndef DOXYGEN_NO_DETAIL
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namespace detail { namespace simplify
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{
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struct simplify_range_insert
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{
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template<typename Range, typename Strategy, typename OutputIterator, typename Distance>
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static inline void apply(Range const& range, OutputIterator out,
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Distance const& max_distance, Strategy const& strategy)
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{
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if (boost::size(range) <= 2 || max_distance < 0)
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{
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std::copy(boost::begin(range), boost::end(range), out);
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}
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else
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{
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strategy.apply(range, out, max_distance);
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}
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}
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};
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struct simplify_copy
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{
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template <typename Range, typename Strategy, typename Distance>
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static inline void apply(Range const& range, Range& out,
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Distance const& , Strategy const& )
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{
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std::copy
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(
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boost::begin(range), boost::end(range), std::back_inserter(out)
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);
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}
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};
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template<std::size_t Minimum>
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struct simplify_range
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{
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template <typename Range, typename Strategy, typename Distance>
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static inline void apply(Range const& range, Range& out,
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Distance const& max_distance, Strategy const& strategy)
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{
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// Call do_container for a linestring / ring
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/* For a RING:
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The first/last point (the closing point of the ring) should maybe
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be excluded because it lies on a line with second/one but last.
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Here it is never excluded.
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Note also that, especially if max_distance is too large,
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the output ring might be self intersecting while the input ring is
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not, although chances are low in normal polygons
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Finally the inputring might have 3 (open) or 4 (closed) points (=correct),
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the output < 3 or 4(=wrong)
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*/
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if (boost::size(range) <= int(Minimum) || max_distance < 0.0)
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{
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simplify_copy::apply(range, out, max_distance, strategy);
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}
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else
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{
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simplify_range_insert::apply
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(
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range, std::back_inserter(out), max_distance, strategy
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);
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}
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}
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};
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struct simplify_polygon
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{
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template <typename Polygon, typename Strategy, typename Distance>
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static inline void apply(Polygon const& poly_in, Polygon& poly_out,
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Distance const& max_distance, Strategy const& strategy)
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{
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typedef typename ring_type<Polygon>::type ring_type;
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int const Minimum = core_detail::closure::minimum_ring_size
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<
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geometry::closure<Polygon>::value
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>::value;
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// Note that if there are inner rings, and distance is too large,
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// they might intersect with the outer ring in the output,
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// while it didn't in the input.
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simplify_range<Minimum>::apply(exterior_ring(poly_in),
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exterior_ring(poly_out),
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max_distance, strategy);
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traits::resize
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<
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typename boost::remove_reference
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<
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typename traits::interior_mutable_type<Polygon>::type
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>::type
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>::apply(interior_rings(poly_out), num_interior_rings(poly_in));
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typename interior_return_type<Polygon const>::type rings_in
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= interior_rings(poly_in);
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typename interior_return_type<Polygon>::type rings_out
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= interior_rings(poly_out);
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BOOST_AUTO_TPL(it_out, boost::begin(rings_out));
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for (BOOST_AUTO_TPL(it_in, boost::begin(rings_in));
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it_in != boost::end(rings_in);
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++it_in, ++it_out)
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{
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simplify_range<Minimum>::apply(*it_in, *it_out, max_distance, strategy);
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}
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}
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};
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}} // namespace detail::simplify
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#endif // DOXYGEN_NO_DETAIL
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#ifndef DOXYGEN_NO_DISPATCH
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namespace dispatch
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{
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template
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<
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typename Geometry,
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typename Tag = typename tag<Geometry>::type
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>
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struct simplify: not_implemented<Tag>
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{};
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template <typename Point>
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struct simplify<Point, point_tag>
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{
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template <typename Distance, typename Strategy>
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static inline void apply(Point const& point, Point& out,
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Distance const& , Strategy const& )
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{
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geometry::convert(point, out);
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}
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};
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template <typename Linestring>
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struct simplify<Linestring, linestring_tag>
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: detail::simplify::simplify_range<2>
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{};
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template <typename Ring>
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struct simplify<Ring, ring_tag>
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: detail::simplify::simplify_range
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<
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core_detail::closure::minimum_ring_size
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<
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geometry::closure<Ring>::value
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>::value
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>
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{};
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template <typename Polygon>
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struct simplify<Polygon, polygon_tag>
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: detail::simplify::simplify_polygon
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{};
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template
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<
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typename Geometry,
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typename Tag = typename tag<Geometry>::type
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>
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struct simplify_insert: not_implemented<Tag>
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{};
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template <typename Linestring>
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struct simplify_insert<Linestring, linestring_tag>
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: detail::simplify::simplify_range_insert
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{};
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template <typename Ring>
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struct simplify_insert<Ring, ring_tag>
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: detail::simplify::simplify_range_insert
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{};
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} // namespace dispatch
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#endif // DOXYGEN_NO_DISPATCH
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/*!
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\brief Simplify a geometry using a specified strategy
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\ingroup simplify
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\tparam Geometry \tparam_geometry
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\tparam Distance A numerical distance measure
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\tparam Strategy A type fulfilling a SimplifyStrategy concept
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\param strategy A strategy to calculate simplification
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\param geometry input geometry, to be simplified
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\param out output geometry, simplified version of the input geometry
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\param max_distance distance (in units of input coordinates) of a vertex
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to other segments to be removed
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\param strategy simplify strategy to be used for simplification, might
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include point-distance strategy
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\image html svg_simplify_country.png "The image below presents the simplified country"
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\qbk{distinguish,with strategy}
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*/
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template<typename Geometry, typename Distance, typename Strategy>
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inline void simplify(Geometry const& geometry, Geometry& out,
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Distance const& max_distance, Strategy const& strategy)
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{
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concept::check<Geometry>();
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BOOST_CONCEPT_ASSERT(
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(concept::SimplifyStrategy<Strategy, typename point_type<Geometry>::type>)
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);
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geometry::clear(out);
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dispatch::simplify<Geometry>::apply(geometry, out, max_distance, strategy);
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}
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/*!
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\brief Simplify a geometry
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\ingroup simplify
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\tparam Geometry \tparam_geometry
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\tparam Distance \tparam_numeric
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\note This version of simplify simplifies a geometry using the default
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strategy (Douglas Peucker),
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\param geometry input geometry, to be simplified
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\param out output geometry, simplified version of the input geometry
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\param max_distance distance (in units of input coordinates) of a vertex
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to other segments to be removed
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\qbk{[include reference/algorithms/simplify.qbk]}
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*/
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template<typename Geometry, typename Distance>
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inline void simplify(Geometry const& geometry, Geometry& out,
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Distance const& max_distance)
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{
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concept::check<Geometry>();
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typedef typename point_type<Geometry>::type point_type;
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typedef typename strategy::distance::services::default_strategy
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<
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segment_tag, point_type
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>::type ds_strategy_type;
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typedef strategy::simplify::douglas_peucker
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<
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point_type, ds_strategy_type
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> strategy_type;
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simplify(geometry, out, max_distance, strategy_type());
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}
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#ifndef DOXYGEN_NO_DETAIL
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namespace detail { namespace simplify
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{
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/*!
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\brief Simplify a geometry, using an output iterator
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and a specified strategy
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\ingroup simplify
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\tparam Geometry \tparam_geometry
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\param geometry input geometry, to be simplified
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\param out output iterator, outputs all simplified points
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\param max_distance distance (in units of input coordinates) of a vertex
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to other segments to be removed
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\param strategy simplify strategy to be used for simplification,
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might include point-distance strategy
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\qbk{distinguish,with strategy}
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\qbk{[include reference/algorithms/simplify.qbk]}
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*/
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template<typename Geometry, typename OutputIterator, typename Distance, typename Strategy>
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inline void simplify_insert(Geometry const& geometry, OutputIterator out,
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Distance const& max_distance, Strategy const& strategy)
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{
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concept::check<Geometry const>();
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BOOST_CONCEPT_ASSERT(
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(concept::SimplifyStrategy<Strategy, typename point_type<Geometry>::type>)
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);
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dispatch::simplify_insert<Geometry>::apply(geometry, out, max_distance, strategy);
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}
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/*!
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\brief Simplify a geometry, using an output iterator
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\ingroup simplify
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\tparam Geometry \tparam_geometry
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\param geometry input geometry, to be simplified
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\param out output iterator, outputs all simplified points
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\param max_distance distance (in units of input coordinates) of a vertex
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to other segments to be removed
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\qbk{[include reference/algorithms/simplify_insert.qbk]}
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*/
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template<typename Geometry, typename OutputIterator, typename Distance>
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inline void simplify_insert(Geometry const& geometry, OutputIterator out,
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Distance const& max_distance)
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{
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typedef typename point_type<Geometry>::type point_type;
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// Concept: output point type = point type of input geometry
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concept::check<Geometry const>();
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concept::check<point_type>();
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typedef typename strategy::distance::services::default_strategy
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<
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segment_tag, point_type
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>::type ds_strategy_type;
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typedef strategy::simplify::douglas_peucker
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<
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point_type, ds_strategy_type
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> strategy_type;
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dispatch::simplify_insert<Geometry>::apply(geometry, out, max_distance, strategy_type());
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}
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}} // namespace detail::simplify
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#endif // DOXYGEN_NO_DETAIL
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_ALGORITHMS_SIMPLIFY_HPP
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