136 lines
4.4 KiB
C++
136 lines
4.4 KiB
C++
// Boost.Geometry
|
|
|
|
// Copyright (c) 2018-2022 Barend Gehrels, Amsterdam, the Netherlands.
|
|
|
|
// This file was modified by Oracle on 2020-2021.
|
|
// Modifications copyright (c) 2020-2021 Oracle and/or its affiliates.
|
|
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
|
|
|
|
// 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/value_type.hpp>
|
|
|
|
#include <boost/geometry/core/radian_access.hpp>
|
|
|
|
#include <boost/geometry/srs/spheroid.hpp>
|
|
#include <boost/geometry/strategies/buffer.hpp>
|
|
#include <boost/geometry/strategies/geographic/buffer_helper.hpp>
|
|
#include <boost/geometry/strategies/geographic/parameters.hpp>
|
|
#include <boost/geometry/util/math.hpp>
|
|
#include <boost/geometry/util/select_calculation_type.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 with a spheroid
|
|
//! \param spheroid The spheroid to be used
|
|
//! \param count Number of points (minimum 3) for the created circle
|
|
explicit inline geographic_point_circle(Spheroid const& spheroid,
|
|
std::size_t count = default_points_per_circle)
|
|
: m_spheroid(spheroid)
|
|
, m_count(get_point_count_for_circle(count))
|
|
{}
|
|
|
|
//! \brief Constructs the strategy
|
|
//! \param count Number of points (minimum 3) for the created circle
|
|
explicit inline geographic_point_circle(std::size_t count = default_points_per_circle)
|
|
: m_count(get_point_count_for_circle(count))
|
|
{}
|
|
|
|
#ifndef DOXYGEN_SHOULD_SKIP_THIS
|
|
//! Fills range_out with a circle around point using distance_strategy
|
|
template
|
|
<
|
|
typename Point,
|
|
typename DistanceStrategy,
|
|
typename RangeOut
|
|
>
|
|
inline void apply(Point const& point,
|
|
DistanceStrategy const& distance_strategy,
|
|
RangeOut& range_out) const
|
|
{
|
|
using calc_t = typename select_calculation_type
|
|
<
|
|
Point,
|
|
typename boost::range_value<RangeOut>::type,
|
|
CalculationType
|
|
>::type;
|
|
|
|
using helper = geographic_buffer_helper<FormulaPolicy, calc_t>;
|
|
|
|
calc_t const lon_rad = get_as_radian<0>(point);
|
|
calc_t const lat_rad = get_as_radian<1>(point);
|
|
|
|
calc_t const buffer_distance = distance_strategy.apply(point,
|
|
point, strategy::buffer::buffer_side_left);
|
|
|
|
calc_t const two_pi = geometry::math::two_pi<calc_t>();
|
|
calc_t const pi = geometry::math::pi<calc_t>();
|
|
|
|
calc_t const diff = two_pi / calc_t(m_count);
|
|
calc_t angle = -pi;
|
|
|
|
for (std::size_t i = 0; i < m_count; i++, angle += diff)
|
|
{
|
|
// If angle is zero, shift angle a tiny bit to avoid spikes.
|
|
calc_t const eps = angle == 0 ? 1.0e-10 : 0.0;
|
|
helper::append_point(lon_rad, lat_rad, buffer_distance, angle + eps, m_spheroid, range_out);
|
|
}
|
|
|
|
{
|
|
// Close the range
|
|
auto const p = range_out.front();
|
|
range_out.push_back(p);
|
|
}
|
|
}
|
|
#endif // DOXYGEN_SHOULD_SKIP_THIS
|
|
|
|
private :
|
|
Spheroid m_spheroid;
|
|
std::size_t m_count;
|
|
};
|
|
|
|
}} // namespace strategy::buffer
|
|
|
|
}} // namespace boost::geometry
|
|
|
|
#endif // BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_POINT_CIRCLE_HPP
|