projections/impl/pj_phi2.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_PHI2_HPP
0040 #define BOOST_GEOMETRY_PROJECTIONS_PHI2_HPP
0041
0042 #include <boost/geometry/srs/projections/exception.hpp>
0043 #include <boost/geometry/srs/projections/impl/pj_strerrno.hpp>
0044 #include <boost/geometry/util/math.hpp>
0045
0046 namespace boost { namespace geometry { namespace projections {
0047 namespace detail {
0048
0049 template <typename T>
0050 inline T pj_phi2(T const& ts, T const& e)
0051 {
0052     static const T TOL = 1.0e-10;
0053     static const int N_ITER = 15;
0054
0055     T eccnth, Phi, con, dphi;
0056     int i;
0057
0058     eccnth = .5 * e;
0059     Phi = geometry::math::half_pi<T>() - 2. * atan (ts);
0060     i = N_ITER;
0061     do {
0062         con = e * sin (Phi);
0063         dphi = geometry::math::half_pi<T>() - 2. * atan (ts * math::pow((T(1) - con) /
0064            (T(1) + con), eccnth)) - Phi;
0065         Phi += dphi;
0066     } while ( geometry::math::abs(dphi) > TOL && --i);
0067     if (i <= 0)
0068         BOOST_THROW_EXCEPTION( projection_exception(error_non_con_inv_phi2) );
0069     return Phi;
0070 }
0071
0072 } // namespace detail
0073 }}} // namespace boost::geometry::projections
0074
0075 #endif