120 lines
3.8 KiB
C++
120 lines
3.8 KiB
C++
// Boost.Geometry
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// Copyright (c) 2022 Barend Gehrels, 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_STRATEGIES_GEOGRAPHIC_BUFFER_SIDE_STRAIGHT_HPP
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#define BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_SIDE_STRAIGHT_HPP
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#include <cstddef>
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#include <boost/range/value_type.hpp>
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#include <boost/geometry/core/radian_access.hpp>
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#include <boost/geometry/srs/spheroid.hpp>
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#include <boost/geometry/strategies/buffer.hpp>
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#include <boost/geometry/strategies/geographic/buffer_helper.hpp>
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#include <boost/geometry/strategies/geographic/parameters.hpp>
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#include <boost/geometry/util/math.hpp>
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#include <boost/geometry/util/select_calculation_type.hpp>
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namespace boost { namespace geometry
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{
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namespace strategy { namespace buffer
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{
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/*!
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\brief Create a straight buffer along a side, on the Earth
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\ingroup strategies
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\details This strategy can be used as SideStrategy for the buffer algorithm.
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*/
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template
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<
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typename FormulaPolicy = strategy::andoyer,
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typename Spheroid = srs::spheroid<double>,
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typename CalculationType = void
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>
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class geographic_side_straight
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{
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public :
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//! \brief Constructs the strategy with a spheroid
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//! \param spheroid The spheroid to be used
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explicit inline geographic_side_straight(Spheroid const& spheroid)
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: m_spheroid(spheroid)
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{}
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//! \brief Constructs the strategy
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inline geographic_side_straight()
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{}
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#ifndef DOXYGEN_SHOULD_SKIP_THIS
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// Returns true if the buffer distance is always the same
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static inline bool equidistant()
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{
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return true;
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}
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template
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<
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typename Point,
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typename DistanceStrategy,
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typename RangeOut
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>
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inline result_code apply(Point const& input_p1, Point const& input_p2,
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buffer_side_selector side,
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DistanceStrategy const& distance_strategy,
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RangeOut& range_out) const
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{
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using calc_t = typename select_calculation_type
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<
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Point,
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typename boost::range_value<RangeOut>::type,
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CalculationType
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>::type;
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using helper = geographic_buffer_helper<FormulaPolicy, calc_t>;
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calc_t const lon1_rad = get_as_radian<0>(input_p1);
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calc_t const lat1_rad = get_as_radian<1>(input_p1);
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calc_t const lon2_rad = get_as_radian<0>(input_p2);
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calc_t const lat2_rad = get_as_radian<1>(input_p2);
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if (lon1_rad == lon2_rad && lat1_rad == lat2_rad)
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{
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// Coordinates are simplified and therefore most often not equal.
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// But if simplify is skipped, or for lines with two
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// equal points, length is 0 and we cannot generate output.
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return result_no_output;
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}
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// Measure the angle from p1 to p2 with the Inverse transformation,
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// and subtract pi/2 to make it perpendicular.
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auto const inv = helper::azimuth(lon1_rad, lat1_rad, input_p2, m_spheroid);
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auto const angle = math::wrap_azimuth_in_radian(inv - geometry::math::half_pi<calc_t>());
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// Calculate the distance and generate two points at that distance
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auto const distance = distance_strategy.apply(input_p1, input_p2, side);
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helper::append_point(lon1_rad, lat1_rad, distance, angle, m_spheroid, range_out);
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helper::append_point(lon2_rad, lat2_rad, distance, angle, m_spheroid, range_out);
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return result_normal;
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}
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#endif // DOXYGEN_SHOULD_SKIP_THIS
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private :
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Spheroid m_spheroid;
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};
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}} // namespace strategy::buffer
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_SIDE_STRAIGHT_HPP
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