116 lines
3.3 KiB
C++
116 lines
3.3 KiB
C++
// Boost.Geometry
|
|
|
|
// Copyright (c) 2021, Oracle and/or its affiliates.
|
|
|
|
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
|
|
|
|
// Licensed under the Boost Software License version 1.0.
|
|
// http://www.boost.org/users/license.html
|
|
|
|
#ifndef BOOST_GEOMETRY_STRATEGY_SPHERICAL_AREA_BOX_HPP
|
|
#define BOOST_GEOMETRY_STRATEGY_SPHERICAL_AREA_BOX_HPP
|
|
|
|
|
|
#include <boost/geometry/core/coordinate_type.hpp>
|
|
#include <boost/geometry/core/coordinate_dimension.hpp>
|
|
#include <boost/geometry/core/radian_access.hpp>
|
|
#include <boost/geometry/srs/sphere.hpp>
|
|
#include <boost/geometry/strategies/spherical/get_radius.hpp>
|
|
#include <boost/geometry/strategy/area.hpp>
|
|
#include <boost/geometry/util/normalize_spheroidal_box_coordinates.hpp>
|
|
|
|
|
|
namespace boost { namespace geometry
|
|
{
|
|
|
|
namespace strategy { namespace area
|
|
{
|
|
|
|
// https://math.stackexchange.com/questions/131735/surface-element-in-spherical-coordinates
|
|
// http://www.cs.cmu.edu/afs/cs/academic/class/16823-s16/www/pdfs/appearance-modeling-3.pdf
|
|
// https://www.astronomyclub.xyz/celestial-sphere-2/solid-angle-on-the-celestial-sphere.html
|
|
// https://mathworld.wolfram.com/SolidAngle.html
|
|
// https://en.wikipedia.org/wiki/Spherical_coordinate_system
|
|
// Note that the equations used in the above articles are spherical polar coordinates.
|
|
// We use spherical equatorial, so the equation is different:
|
|
// assume(y_max > y_min);
|
|
// assume(x_max > x_min);
|
|
// /* because of polar to equatorial conversion */
|
|
// sin(%pi / 2 - y);
|
|
// O: r ^ 2 * cos(y);
|
|
// S: integrate(integrate(O, y, y_min, y_max), x, x_min, x_max);
|
|
template
|
|
<
|
|
typename RadiusTypeOrSphere = double,
|
|
typename CalculationType = void
|
|
>
|
|
class spherical_box
|
|
{
|
|
typedef typename strategy_detail::get_radius
|
|
<
|
|
RadiusTypeOrSphere
|
|
>::type radius_type;
|
|
|
|
public:
|
|
template <typename Box>
|
|
struct result_type
|
|
: strategy::area::detail::result_type
|
|
<
|
|
Box,
|
|
CalculationType
|
|
>
|
|
{};
|
|
|
|
// For consistency with other strategies the radius is set to 1
|
|
inline spherical_box()
|
|
: m_radius(1.0)
|
|
{}
|
|
|
|
template <typename RadiusOrSphere>
|
|
explicit inline spherical_box(RadiusOrSphere const& radius_or_sphere)
|
|
: m_radius(strategy_detail::get_radius
|
|
<
|
|
RadiusOrSphere
|
|
>::apply(radius_or_sphere))
|
|
{}
|
|
|
|
template <typename Box>
|
|
inline auto apply(Box const& box) const
|
|
{
|
|
typedef typename result_type<Box>::type return_type;
|
|
|
|
return_type x_min = get_as_radian<min_corner, 0>(box); // lon
|
|
return_type y_min = get_as_radian<min_corner, 1>(box); // lat
|
|
return_type x_max = get_as_radian<max_corner, 0>(box);
|
|
return_type y_max = get_as_radian<max_corner, 1>(box);
|
|
|
|
if (x_min == x_max || y_max == y_min)
|
|
{
|
|
return return_type(0);
|
|
}
|
|
|
|
math::normalize_spheroidal_box_coordinates<radian>(x_min, y_min, x_max, y_max);
|
|
|
|
return (x_max - x_min)
|
|
* (sin(y_max) - sin(y_min))
|
|
* return_type(m_radius * m_radius);
|
|
}
|
|
|
|
srs::sphere<radius_type> model() const
|
|
{
|
|
return srs::sphere<radius_type>(m_radius);
|
|
}
|
|
|
|
private:
|
|
radius_type m_radius;
|
|
};
|
|
|
|
|
|
}} // namespace strategy::area
|
|
|
|
|
|
}} // namespace boost::geometry
|
|
|
|
|
|
#endif // BOOST_GEOMETRY_STRATEGY_SPHERICAL_AREA_BOX_HPP
|