projections/impl/pj_auth.hpp

0001 // Boost.Geometry (aka GGL, Generic Geometry Library)
0002 // This file is manually converted from PROJ4
0003
0004 // Copyright (c) 2008-2012 Barend Gehrels, Amsterdam, the Netherlands.
0005
0006 // This file was modified by Oracle on 2017, 2018.
0007 // Modifications copyright (c) 2017-2018, Oracle and/or its affiliates.
0008 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0009
0010 // Use, modification and distribution is subject to the Boost Software License,
0011 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0012 // http://www.boost.org/LICENSE_1_0.txt)
0013
0014 // This file is converted from PROJ4, http://trac.osgeo.org/proj
0015 // PROJ4 is originally written by Gerald Evenden (then of the USGS)
0016 // PROJ4 is maintained by Frank Warmerdam
0017 // PROJ4 is converted to Geometry Library by Barend Gehrels (Geodan, Amsterdam)
0018
0019 // Original copyright notice:
0020
0021 // Permission is hereby granted, free of charge, to any person obtaining a
0022 // copy of this software and associated documentation files (the "Software"),
0023 // to deal in the Software without restriction, including without limitation
0024 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
0025 // and/or sell copies of the Software, and to permit persons to whom the
0026 // Software is furnished to do so, subject to the following conditions:
0027
0028 // The above copyright notice and this permission notice shall be included
0029 // in all copies or substantial portions of the Software.
0030
0031 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
0032 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0033 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
0034 // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
0035 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
0036 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
0037 // DEALINGS IN THE SOFTWARE.
0038
0039 #ifndef BOOST_GEOMETRY_PROJECTIONS_IMPL_PJ_AUTH_HPP
0040 #define BOOST_GEOMETRY_PROJECTIONS_IMPL_PJ_AUTH_HPP
0041
0042 #include <cassert>
0043 #include <cmath>
0044
0045 #include <boost/geometry/core/assert.hpp>
0046
0047 namespace boost { namespace geometry { namespace projections {
0048
0049 namespace detail {
0050
0051 template <typename T>
0052 struct apa
0053 {
0054     static const std::size_t size = 3;
0055
0056     T const& operator[](size_t i) const { return data[i]; }
0057     T & operator[](size_t i) { return data[i]; }
0058
0059 private:
0060     T data[3];
0061 };
0062
0063 /* determine latitude from authalic latitude */
0064 template <typename T>
0065 inline detail::apa<T> pj_authset(T const& es)
0066 {
0067     static const T P00 = .33333333333333333333;
0068     static const T P01 = .17222222222222222222;
0069     static const T P02 = .10257936507936507936;
0070     static const T P10 = .06388888888888888888;
0071     static const T P11 = .06640211640211640211;
0072     static const T P20 = .01641501294219154443;
0073
0074     T t = 0;
0075     detail::apa<T> apa;
0076
0077     {
0078         apa[0] = es * P00;
0079         t = es * es;
0080         apa[0] += t * P01;
0081         apa[1] = t * P10;
0082         t *= es;
0083         apa[0] += t * P02;
0084         apa[1] += t * P11;
0085         apa[2] = t * P20;
0086     }
0087
0088     return apa;
0089 }
0090
0091 template <typename T>
0092 inline T pj_authlat(T const& beta, detail::apa<T> const& apa)
0093 {
0094     T const t = beta + beta;
0095
0096     return(beta + apa[0] * sin(t) + apa[1] * sin(t + t) + apa[2] * sin(t + t + t));
0097 }
0098
0099 } // namespace detail
0100 }}} // namespace boost::geometry::projections
0101
0102 #endif // BOOST_GEOMETRY_PROJECTIONS_IMPL_PJ_AUTH_HPP