123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133 |
- // Boost.Geometry
- // Copyright (c) 2018-2019 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_STRATEGIES_GEOGRAPHIC_BUFFER_POINT_CIRCLE_HPP
- #define BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_POINT_CIRCLE_HPP
- #include <cstddef>
- #include <boost/range.hpp>
- #include <boost/geometry/util/math.hpp>
- #include <boost/geometry/strategies/buffer.hpp>
- namespace boost { namespace geometry
- {
- namespace strategy { namespace buffer
- {
- /*!
- \brief Create a circular buffer around a point, on the Earth
- \ingroup strategies
- \details This strategy can be used as PointStrategy for the buffer algorithm.
- It creates a circular buffer around a point, on the Earth. It can be applied
- for points and multi_points.
- \qbk{
- [heading Example]
- [buffer_geographic_point_circle]
- [buffer_geographic_point_circle_output]
- [heading See also]
- \* [link geometry.reference.algorithms.buffer.buffer_7_with_strategies buffer (with strategies)]
- \* [link geometry.reference.strategies.strategy_buffer_point_circle point_circle]
- \* [link geometry.reference.strategies.strategy_buffer_point_square point_square]
- }
- */
- template
- <
- typename FormulaPolicy = strategy::andoyer,
- typename Spheroid = srs::spheroid<double>,
- typename CalculationType = void
- >
- class geographic_point_circle
- {
- public :
- //! \brief Constructs the strategy
- //! \param count number of points for the created circle (if count
- //! is smaller than 3, count is internally set to 3)
- explicit geographic_point_circle(std::size_t count = 90)
- : m_count((count < 3u) ? 3u : count)
- {}
- #ifndef DOXYGEN_SHOULD_SKIP_THIS
- //! Fills output_range with a circle around point using distance_strategy
- template
- <
- typename Point,
- typename OutputRange,
- typename DistanceStrategy
- >
- inline void apply(Point const& point,
- DistanceStrategy const& distance_strategy,
- OutputRange& output_range) const
- {
- typedef typename boost::range_value<OutputRange>::type output_point_type;
- typedef typename select_most_precise
- <
- typename geometry::coordinate_type<Point>::type,
- typename geometry::coordinate_type<output_point_type>::type,
- CalculationType
- //double
- >::type calculation_type;
- calculation_type const buffer_distance = distance_strategy.apply(point, point,
- strategy::buffer::buffer_side_left);
- typedef typename FormulaPolicy::template direct
- <
- calculation_type, true, false, false, false
- > direct_t;
- calculation_type const two_pi = geometry::math::two_pi<calculation_type>();
- calculation_type const pi = geometry::math::pi<calculation_type>();
- calculation_type const diff = two_pi / calculation_type(m_count);
- // TODO: after calculation of some angles is corrected,
- // we can start at 0.0
- calculation_type angle = 0.001;
- for (std::size_t i = 0; i < m_count; i++, angle += diff)
- {
- if (angle > pi)
- {
- angle -= two_pi;
- }
- typename direct_t::result_type
- dir_r = direct_t::apply(get_as_radian<0>(point), get_as_radian<1>(point),
- buffer_distance, angle,
- m_spheroid);
- output_point_type p;
- set_from_radian<0>(p, dir_r.lon2);
- set_from_radian<1>(p, dir_r.lat2);
- output_range.push_back(p);
- }
- {
- // Close the range
- const output_point_type p = output_range.front();
- output_range.push_back(p);
- }
- }
- #endif // DOXYGEN_SHOULD_SKIP_THIS
- private :
- std::size_t m_count;
- Spheroid m_spheroid;
- };
- }} // namespace strategy::buffer
- }} // namespace boost::geometry
- #endif // BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_POINT_CIRCLE_HPP
|