]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands. | |
4 | ||
5 | // This file was modified by Oracle on 2014. | |
6 | // Modifications copyright (c) 2014, Oracle and/or its affiliates. | |
7 | ||
8 | // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle | |
9 | ||
10 | // Use, modification and distribution is subject to the Boost Software License, | |
11 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
12 | // http://www.boost.org/LICENSE_1_0.txt) | |
13 | ||
14 | #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_AZIMUTH_HPP | |
15 | #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_AZIMUTH_HPP | |
16 | ||
17 | #include <boost/geometry/core/cs.hpp> | |
18 | #include <boost/geometry/core/access.hpp> | |
19 | #include <boost/geometry/core/radian_access.hpp> | |
20 | #include <boost/geometry/core/tags.hpp> | |
21 | ||
22 | #include <boost/geometry/util/math.hpp> | |
23 | ||
24 | #include <boost/geometry/algorithms/not_implemented.hpp> | |
25 | #include <boost/geometry/algorithms/detail/vincenty_inverse.hpp> | |
26 | ||
27 | namespace boost { namespace geometry | |
28 | { | |
29 | ||
30 | // An azimuth is an angle between a vector/segment from origin to a point of | |
31 | // interest and a reference vector. Typically north-based azimuth is used. | |
32 | // North direction is used as a reference, angle is measured clockwise | |
33 | // (North - 0deg, East - 90deg). For consistency in 2d cartesian CS | |
34 | // the reference vector is Y axis, angle is measured clockwise. | |
35 | // http://en.wikipedia.org/wiki/Azimuth | |
36 | ||
37 | #ifndef DOXYGEN_NO_DISPATCH | |
38 | namespace detail_dispatch | |
39 | { | |
40 | ||
41 | template <typename ReturnType, typename Tag> | |
42 | struct azimuth | |
43 | : not_implemented<Tag> | |
44 | {}; | |
45 | ||
46 | template <typename ReturnType> | |
47 | struct azimuth<ReturnType, geographic_tag> | |
48 | { | |
49 | template <typename P1, typename P2, typename Spheroid> | |
50 | static inline ReturnType apply(P1 const& p1, P2 const& p2, Spheroid const& spheroid) | |
51 | { | |
52 | return geometry::detail::vincenty_inverse<ReturnType, false, true>().apply | |
53 | ( get_as_radian<0>(p1), get_as_radian<1>(p1), | |
54 | get_as_radian<0>(p2), get_as_radian<1>(p2), | |
55 | spheroid ).azimuth; | |
56 | } | |
57 | ||
58 | template <typename P1, typename P2> | |
59 | static inline ReturnType apply(P1 const& p1, P2 const& p2) | |
60 | { | |
61 | return apply(p1, p2, srs::spheroid<ReturnType>()); | |
62 | } | |
63 | }; | |
64 | ||
65 | template <typename ReturnType> | |
66 | struct azimuth<ReturnType, spherical_equatorial_tag> | |
67 | { | |
68 | template <typename P1, typename P2, typename Sphere> | |
69 | static inline ReturnType apply(P1 const& p1, P2 const& p2, Sphere const& /*unused*/) | |
70 | { | |
71 | // http://williams.best.vwh.net/avform.htm#Crs | |
72 | ReturnType dlon = get_as_radian<0>(p2) - get_as_radian<0>(p1); | |
73 | ReturnType cos_p2lat = cos(get_as_radian<1>(p2)); | |
74 | ||
75 | // An optimization which should kick in often for Boxes | |
76 | //if ( math::equals(dlon, ReturnType(0)) ) | |
77 | //if ( get<0>(p1) == get<0>(p2) ) | |
78 | //{ | |
79 | // return - sin(get_as_radian<1>(p1)) * cos_p2lat); | |
80 | //} | |
81 | ||
82 | // "An alternative formula, not requiring the pre-computation of d" | |
83 | // In the formula below dlon is used as "d" | |
84 | return atan2(sin(dlon) * cos_p2lat, | |
85 | cos(get_as_radian<1>(p1)) * sin(get_as_radian<1>(p2)) | |
86 | - sin(get_as_radian<1>(p1)) * cos_p2lat * cos(dlon)); | |
87 | } | |
88 | ||
89 | template <typename P1, typename P2> | |
90 | static inline ReturnType apply(P1 const& p1, P2 const& p2) | |
91 | { | |
92 | return apply(p1, p2, 0); // dummy model | |
93 | } | |
94 | }; | |
95 | ||
96 | template <typename ReturnType> | |
97 | struct azimuth<ReturnType, spherical_polar_tag> | |
98 | : azimuth<ReturnType, spherical_equatorial_tag> | |
99 | {}; | |
100 | ||
101 | template <typename ReturnType> | |
102 | struct azimuth<ReturnType, cartesian_tag> | |
103 | { | |
104 | template <typename P1, typename P2, typename Plane> | |
105 | static inline ReturnType apply(P1 const& p1, P2 const& p2, Plane const& /*unused*/) | |
106 | { | |
107 | ReturnType x = get<0>(p2) - get<0>(p1); | |
108 | ReturnType y = get<1>(p2) - get<1>(p1); | |
109 | ||
110 | // NOTE: azimuth 0 is at Y axis, increasing right | |
111 | // as in spherical/geographic where 0 is at North axis | |
112 | return atan2(x, y); | |
113 | } | |
114 | ||
115 | template <typename P1, typename P2> | |
116 | static inline ReturnType apply(P1 const& p1, P2 const& p2) | |
117 | { | |
118 | return apply(p1, p2, 0); // dummy model | |
119 | } | |
120 | }; | |
121 | ||
122 | } // detail_dispatch | |
123 | #endif // DOXYGEN_NO_DISPATCH | |
124 | ||
125 | #ifndef DOXYGEN_NO_DETAIL | |
126 | namespace detail | |
127 | { | |
128 | ||
129 | /// Calculate azimuth between two points. | |
130 | /// The result is in radians. | |
131 | template <typename ReturnType, typename Point1, typename Point2> | |
132 | inline ReturnType azimuth(Point1 const& p1, Point2 const& p2) | |
133 | { | |
134 | return detail_dispatch::azimuth | |
135 | < | |
136 | ReturnType, | |
137 | typename geometry::cs_tag<Point1>::type | |
138 | >::apply(p1, p2); | |
139 | } | |
140 | ||
141 | /// Calculate azimuth between two points. | |
142 | /// The result is in radians. | |
143 | template <typename ReturnType, typename Point1, typename Point2, typename Model> | |
144 | inline ReturnType azimuth(Point1 const& p1, Point2 const& p2, Model const& model) | |
145 | { | |
146 | return detail_dispatch::azimuth | |
147 | < | |
148 | ReturnType, | |
149 | typename geometry::cs_tag<Point1>::type | |
150 | >::apply(p1, p2, model); | |
151 | } | |
152 | ||
153 | } // namespace detail | |
154 | #endif // DOXYGEN_NO_DETAIL | |
155 | ||
156 | }} // namespace boost::geometry | |
157 | ||
158 | #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_AZIMUTH_HPP |