strategies/spherical/ssf.hpp

0001 // Boost.Geometry (aka GGL, Generic Geometry Library)
0002
0003 // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
0004
0005 // This file was modified by Oracle on 2016-2021.
0006 // Modifications copyright (c) 2016-2021, Oracle and/or its affiliates.
0007 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0008
0009 // Use, modification and distribution is subject to the Boost Software License,
0010 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0011 // http://www.boost.org/LICENSE_1_0.txt)
0012
0013 #ifndef BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
0014 #define BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
0015
0016
0017 #include <boost/geometry/core/cs.hpp>
0018 #include <boost/geometry/core/access.hpp>
0019 #include <boost/geometry/core/coordinate_promotion.hpp>
0020 #include <boost/geometry/core/radian_access.hpp>
0021
0022 #include <boost/geometry/util/math.hpp>
0023 #include <boost/geometry/util/select_calculation_type.hpp>
0024
0025 #include <boost/geometry/strategy/spherical/envelope.hpp>
0026
0027 #include <boost/geometry/strategies/side.hpp>
0028 #include <boost/geometry/strategies/spherical/disjoint_segment_box.hpp>
0029 //#include <boost/geometry/strategies/concepts/side_concept.hpp>
0030 #include <boost/geometry/strategies/spherical/point_in_point.hpp>
0031
0032
0033 namespace boost { namespace geometry
0034 {
0035
0036
0037 namespace strategy { namespace side
0038 {
0039
0040 #ifndef DOXYGEN_NO_DETAIL
0041 namespace detail
0042 {
0043
0044 template <typename T>
0045 int spherical_side_formula(T const& lambda1, T const& delta1,
0046                            T const& lambda2, T const& delta2,
0047                            T const& lambda, T const& delta)
0048 {
0049     // Create temporary points (vectors) on unit a sphere
0050     T const cos_delta1 = cos(delta1);
0051     T const c1x = cos_delta1 * cos(lambda1);
0052     T const c1y = cos_delta1 * sin(lambda1);
0053     T const c1z = sin(delta1);
0054
0055     T const cos_delta2 = cos(delta2);
0056     T const c2x = cos_delta2 * cos(lambda2);
0057     T const c2y = cos_delta2 * sin(lambda2);
0058     T const c2z = sin(delta2);
0059
0060     // (Third point is converted directly)
0061     T const cos_delta = cos(delta);
0062
0063     // Apply the "Spherical Side Formula" as presented on my blog
0064     T const dist
0065         = (c1y * c2z - c1z * c2y) * cos_delta * cos(lambda)
0066         + (c1z * c2x - c1x * c2z) * cos_delta * sin(lambda)
0067         + (c1x * c2y - c1y * c2x) * sin(delta);
0068
0069     T zero = T();
0070     return math::equals(dist, zero) ? 0
0071         : dist > zero ? 1
0072         : -1; // dist < zero
0073 }
0074
0075 }
0076 #endif // DOXYGEN_NO_DETAIL
0077
0078 /*!
0079 \brief Check at which side of a Great Circle segment a point lies
0080          left of segment (> 0), right of segment (< 0), on segment (0)
0081 \ingroup strategies
0082 \tparam CalculationType \tparam_calculation
0083  */
0084 template <typename CalculationType = void>
0085 class spherical_side_formula
0086 {
0087
0088 public :
0089     typedef spherical_tag cs_tag;
0090
0091     template <typename P1, typename P2, typename P>
0092     static inline int apply(P1 const& p1, P2 const& p2, P const& p)
0093     {
0094         typedef typename promote_floating_point
0095             <
0096                 typename select_calculation_type_alt
0097                     <
0098                         CalculationType,
0099                         P1, P2, P
0100                     >::type
0101             >::type calculation_type;
0102
0103         calculation_type const lambda1 = get_as_radian<0>(p1);
0104         calculation_type const delta1 = get_as_radian<1>(p1);
0105         calculation_type const lambda2 = get_as_radian<0>(p2);
0106         calculation_type const delta2 = get_as_radian<1>(p2);
0107         calculation_type const lambda = get_as_radian<0>(p);
0108         calculation_type const delta = get_as_radian<1>(p);
0109
0110         return detail::spherical_side_formula(lambda1, delta1,
0111                                               lambda2, delta2,
0112                                               lambda, delta);
0113     }
0114 };
0115
0116
0117 #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
0118 namespace services
0119 {
0120
0121 /*template <typename CalculationType>
0122 struct default_strategy<spherical_polar_tag, CalculationType>
0123 {
0124     typedef spherical_side_formula<CalculationType> type;
0125 };*/
0126
0127 template <typename CalculationType>
0128 struct default_strategy<spherical_equatorial_tag, CalculationType>
0129 {
0130     typedef spherical_side_formula<CalculationType> type;
0131 };
0132
0133 template <typename CalculationType>
0134 struct default_strategy<geographic_tag, CalculationType>
0135 {
0136     typedef spherical_side_formula<CalculationType> type;
0137 };
0138
0139 }
0140 #endif
0141
0142 }} // namespace strategy::side
0143
0144 }} // namespace boost::geometry
0145
0146
0147 #endif // BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP