pj_tsfn.hpp 2.4 KB

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  1. // Boost.Geometry (aka GGL, Generic Geometry Library)
  2. // This file is manually converted from PROJ4
  3. // Copyright (c) 2008-2012 Barend Gehrels, Amsterdam, the Netherlands.
  4. // This file was modified by Oracle on 2017, 2018.
  5. // Modifications copyright (c) 2017-2018, Oracle and/or its affiliates.
  6. // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
  7. // Use, modification and distribution is subject to the Boost Software License,
  8. // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  9. // http://www.boost.org/LICENSE_1_0.txt)
  10. // This file is converted from PROJ4, http://trac.osgeo.org/proj
  11. // PROJ4 is originally written by Gerald Evenden (then of the USGS)
  12. // PROJ4 is maintained by Frank Warmerdam
  13. // PROJ4 is converted to Geometry Library by Barend Gehrels (Geodan, Amsterdam)
  14. // Original copyright notice:
  15. // Permission is hereby granted, free of charge, to any person obtaining a
  16. // copy of this software and associated documentation files (the "Software"),
  17. // to deal in the Software without restriction, including without limitation
  18. // the rights to use, copy, modify, merge, publish, distribute, sublicense,
  19. // and/or sell copies of the Software, and to permit persons to whom the
  20. // Software is furnished to do so, subject to the following conditions:
  21. // The above copyright notice and this permission notice shall be included
  22. // in all copies or substantial portions of the Software.
  23. // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  24. // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  25. // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  26. // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  27. // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  28. // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  29. // DEALINGS IN THE SOFTWARE.
  30. #ifndef BOOST_GEOMETRY_PROJECTIONS_PJ_TSFN_HPP
  31. #define BOOST_GEOMETRY_PROJECTIONS_PJ_TSFN_HPP
  32. #include <boost/geometry/util/math.hpp>
  33. namespace boost { namespace geometry { namespace projections {
  34. namespace detail {
  35. /* determine small t */
  36. template <typename T>
  37. inline T pj_tsfn(T const& phi, T sinphi, T const& e)
  38. {
  39. sinphi *= e;
  40. return (tan (.5 * (geometry::math::half_pi<T>() - phi)) /
  41. math::pow((T(1) - sinphi) / (T(1) + sinphi), T(0.5) * e));
  42. }
  43. } // namespace detail
  44. }}} // namespace boost::geometry::projections
  45. #endif