1 // Boost.Geometry (aka GGL, Generic Geometry Library) 2 // This file is manually converted from PROJ4 3 4 // Copyright (c) 2008-2012 Barend Gehrels, Amsterdam, the Netherlands. 5 6 // This file was modified by Oracle on 2017, 2018. 7 // Modifications copyright (c) 2017-2018, Oracle and/or its affiliates. 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 // This file is converted from PROJ4, http://trac.osgeo.org/proj 15 // PROJ4 is originally written by Gerald Evenden (then of the USGS) 16 // PROJ4 is maintained by Frank Warmerdam 17 // PROJ4 is converted to Geometry Library by Barend Gehrels (Geodan, Amsterdam) 18 19 // Original copyright notice: 20 21 // Permission is hereby granted, free of charge, to any person obtaining a 22 // copy of this software and associated documentation files (the "Software"), 23 // to deal in the Software without restriction, including without limitation 24 // the rights to use, copy, modify, merge, publish, distribute, sublicense, 25 // and/or sell copies of the Software, and to permit persons to whom the 26 // Software is furnished to do so, subject to the following conditions: 27 28 // The above copyright notice and this permission notice shall be included 29 // in all copies or substantial portions of the Software. 30 31 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 32 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 33 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 34 // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 35 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 36 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 37 // DEALINGS IN THE SOFTWARE. 38 39 #ifndef BOOST_GEOMETRY_PROJECTIONS_PJ_TSFN_HPP 40 #define BOOST_GEOMETRY_PROJECTIONS_PJ_TSFN_HPP 41 42 #include <boost/geometry/util/math.hpp> 43 44 namespace boost { namespace geometry { namespace projections { 45 namespace detail { 46 47 /* determine small t */ 48 template <typename T> pj_tsfn(T const & phi,T sinphi,T const & e)49 inline T pj_tsfn(T const& phi, T sinphi, T const& e) 50 { 51 sinphi *= e; 52 return (tan (.5 * (geometry::math::half_pi<T>() - phi)) / 53 math::pow((T(1) - sinphi) / (T(1) + sinphi), T(0.5) * e)); 54 } 55 56 } // namespace detail 57 }}} // namespace boost::geometry::projections 58 #endif 59