strategy/spherical/expand_point.hpp

0001 // Boost.Geometry (aka GGL, Generic Geometry Library)
0002
0003 // Copyright (c) 2007-2015 Barend Gehrels, Amsterdam, the Netherlands.
0004 // Copyright (c) 2008-2015 Bruno Lalande, Paris, France.
0005 // Copyright (c) 2009-2015 Mateusz Loskot, London, UK.
0006 // Copyright (c) 2014-2015 Samuel Debionne, Grenoble, France.
0007
0008 // This file was modified by Oracle on 2015-2020.
0009 // Modifications copyright (c) 2015-2020, Oracle and/or its affiliates.
0010
0011 // Contributed and/or modified by Vissarion Fysikopoulos, on behalf of Oracle
0012 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
0013 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0014
0015 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
0016 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
0017
0018 // Distributed under the Boost Software License, Version 1.0.
0019 // (See accompanying file LICENSE_1_0.txt or copy at
0020 // http://www.boost.org/LICENSE_1_0.txt)
0021
0022 #ifndef BOOST_GEOMETRY_STRATEGY_SPHERICAL_EXPAND_POINT_HPP
0023 #define BOOST_GEOMETRY_STRATEGY_SPHERICAL_EXPAND_POINT_HPP
0024
0025 #include <algorithm>
0026 #include <cstddef>
0027 #include <functional>
0028 #include <type_traits>
0029
0030 #include <boost/geometry/core/access.hpp>
0031 #include <boost/geometry/core/coordinate_dimension.hpp>
0032 #include <boost/geometry/core/coordinate_system.hpp>
0033 #include <boost/geometry/core/coordinate_type.hpp>
0034 #include <boost/geometry/core/tags.hpp>
0035
0036 #include <boost/geometry/util/is_inverse_spheroidal_coordinates.hpp>
0037 #include <boost/geometry/util/math.hpp>
0038 #include <boost/geometry/util/select_coordinate_type.hpp>
0039
0040 #include <boost/geometry/algorithms/detail/normalize.hpp>
0041 #include <boost/geometry/algorithms/detail/envelope/transform_units.hpp>
0042
0043 #include <boost/geometry/strategy/expand.hpp>
0044 #include <boost/geometry/strategy/cartesian/expand_point.hpp>
0045
0046
0047 namespace boost { namespace geometry
0048 {
0049
0050 namespace strategy { namespace expand
0051 {
0052
0053 #ifndef DOXYGEN_NO_DETAIL
0054 namespace detail
0055 {
0056
0057 // implementation for the spherical and geographic coordinate systems
0058 template <std::size_t DimensionCount, bool IsEquatorial>
0059 struct point_loop_on_spheroid
0060 {
0061     template <typename Box, typename Point>
0062     static inline void apply(Box& box, Point const& point)
0063     {
0064         typedef typename point_type<Box>::type box_point_type;
0065         typedef typename coordinate_type<Box>::type box_coordinate_type;
0066         typedef typename geometry::detail::cs_angular_units<Box>::type units_type;
0067
0068         typedef math::detail::constants_on_spheroid
0069             <
0070                 box_coordinate_type,
0071                 units_type
0072             > constants;
0073
0074         // normalize input point and input box
0075         Point p_normalized;
0076         strategy::normalize::spherical_point::apply(point, p_normalized);
0077
0078         // transform input point to be of the same type as the box point
0079         box_point_type box_point;
0080         geometry::detail::envelope::transform_units(p_normalized, box_point);
0081
0082         if (is_inverse_spheroidal_coordinates(box))
0083         {
0084             geometry::set_from_radian<min_corner, 0>(box, geometry::get_as_radian<0>(p_normalized));
0085             geometry::set_from_radian<min_corner, 1>(box, geometry::get_as_radian<1>(p_normalized));
0086             geometry::set_from_radian<max_corner, 0>(box, geometry::get_as_radian<0>(p_normalized));
0087             geometry::set_from_radian<max_corner, 1>(box, geometry::get_as_radian<1>(p_normalized));
0088
0089         } else {
0090
0091             strategy::normalize::spherical_box::apply(box, box);
0092
0093             box_coordinate_type p_lon = geometry::get<0>(box_point);
0094             box_coordinate_type p_lat = geometry::get<1>(box_point);
0095
0096             typename coordinate_type<Box>::type
0097                     b_lon_min = geometry::get<min_corner, 0>(box),
0098                     b_lat_min = geometry::get<min_corner, 1>(box),
0099                     b_lon_max = geometry::get<max_corner, 0>(box),
0100                     b_lat_max = geometry::get<max_corner, 1>(box);
0101
0102             if (math::is_latitude_pole<units_type, IsEquatorial>(p_lat))
0103             {
0104                 // the point of expansion is the either the north or the
0105                 // south pole; the only important coordinate here is the
0106                 // pole's latitude, as the longitude can be anything;
0107                 // we, thus, take into account the point's latitude only and return
0108                 geometry::set<min_corner, 1>(box, (std::min)(p_lat, b_lat_min));
0109                 geometry::set<max_corner, 1>(box, (std::max)(p_lat, b_lat_max));
0110                 return;
0111             }
0112
0113             if (math::equals(b_lat_min, b_lat_max)
0114                     && math::is_latitude_pole<units_type, IsEquatorial>(b_lat_min))
0115             {
0116                 // the box degenerates to either the north or the south pole;
0117                 // the only important coordinate here is the pole's latitude,
0118                 // as the longitude can be anything;
0119                 // we thus take into account the box's latitude only and return
0120                 geometry::set<min_corner, 0>(box, p_lon);
0121                 geometry::set<min_corner, 1>(box, (std::min)(p_lat, b_lat_min));
0122                 geometry::set<max_corner, 0>(box, p_lon);
0123                 geometry::set<max_corner, 1>(box, (std::max)(p_lat, b_lat_max));
0124                 return;
0125             }
0126
0127             // update latitudes
0128             b_lat_min = (std::min)(b_lat_min, p_lat);
0129             b_lat_max = (std::max)(b_lat_max, p_lat);
0130
0131             // update longitudes
0132             if (math::smaller(p_lon, b_lon_min))
0133             {
0134                 box_coordinate_type p_lon_shifted = p_lon + constants::period();
0135
0136                 if (math::larger(p_lon_shifted, b_lon_max))
0137                 {
0138                     // here we could check using: ! math::larger(.., ..)
0139                     if (math::smaller(b_lon_min - p_lon, p_lon_shifted - b_lon_max))
0140                     {
0141                         b_lon_min = p_lon;
0142                     }
0143                     else
0144                     {
0145                         b_lon_max = p_lon_shifted;
0146                     }
0147                 }
0148             }
0149             else if (math::larger(p_lon, b_lon_max))
0150             {
0151                 // in this case, and since p_lon is normalized in the range
0152                 // (-180, 180], we must have that b_lon_max <= 180
0153                 if (b_lon_min < 0
0154                         && math::larger(p_lon - b_lon_max,
0155                                         constants::period() - p_lon + b_lon_min))
0156                 {
0157                     b_lon_min = p_lon;
0158                     b_lon_max += constants::period();
0159                 }
0160                 else
0161                 {
0162                     b_lon_max = p_lon;
0163                 }
0164             }
0165
0166             geometry::set<min_corner, 0>(box, b_lon_min);
0167             geometry::set<min_corner, 1>(box, b_lat_min);
0168             geometry::set<max_corner, 0>(box, b_lon_max);
0169             geometry::set<max_corner, 1>(box, b_lat_max);
0170         }
0171
0172         point_loop
0173             <
0174                 2, DimensionCount
0175             >::apply(box, point);
0176     }
0177 };
0178
0179
0180 } // namespace detail
0181 #endif // DOXYGEN_NO_DETAIL
0182
0183
0184 struct spherical_point
0185 {
0186     template <typename Box, typename Point>
0187     static void apply(Box & box, Point const& point)
0188     {
0189         expand::detail::point_loop_on_spheroid
0190             <
0191                 dimension<Point>::value,
0192                 ! std::is_same<typename cs_tag<Point>::type, spherical_polar_tag>::value
0193             >::apply(box, point);
0194     }
0195 };
0196
0197
0198 #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
0199
0200 namespace services
0201 {
0202
0203 template <typename CalculationType>
0204 struct default_strategy<point_tag, spherical_equatorial_tag, CalculationType>
0205 {
0206     typedef spherical_point type;
0207 };
0208
0209 template <typename CalculationType>
0210 struct default_strategy<point_tag, spherical_polar_tag, CalculationType>
0211 {
0212     typedef spherical_point type;
0213 };
0214
0215 template <typename CalculationType>
0216 struct default_strategy<point_tag, geographic_tag, CalculationType>
0217 {
0218     typedef spherical_point type;
0219 };
0220
0221
0222 } // namespace services
0223
0224 #endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
0225
0226
0227 }} // namespace strategy::expand
0228
0229 }} // namespace boost::geometry
0230
0231 #endif // BOOST_GEOMETRY_STRATEGY_SPHERICAL_EXPAND_POINT_HPP