ceph/src/boost/libs/geometry/doc/src/examples/algorithms/length_with_strategy.cpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2 // QuickBook Example
   3
   4 // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
   5
   6 // Use, modification and distribution is subject to the Boost Software License,
   7 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   8 // http://www.boost.org/LICENSE_1_0.txt)
   9
  10 //[length_with_strategy
  11 //`The following example shows the length measured over a sphere, expressed in kilometers. To do that the radius of the sphere must be specified in the constructor of the strategy.
  12
  13 #include <iostream>
  14 #include <boost/geometry.hpp>
  15 #include <boost/geometry/geometries/linestring.hpp>
  16
  17 int main()
  18 {
  19     using namespace boost::geometry;
  20     typedef model::point<float, 2, cs::spherical_equatorial<degree> > P;
  21     model::linestring<P> line;
  22     line.push_back(P(2, 41));
  23     line.push_back(P(2, 48));
  24     line.push_back(P(5, 52));
  25     double const mean_radius = 6371.0; /*< [@http://en.wikipedia.org/wiki/Earth_radius Wiki]  >*/
  26     std::cout << "length is "
  27         << length(line, strategy::distance::haversine<float>(mean_radius) )
  28         << " kilometers " << std::endl;
  29
  30     return 0;
  31 }
  32
  33 //]
  34
  35
  36 //[length_with_strategy_output
  37 /*`
  38 Output:
  39 [pre
  40 length is 1272.03 kilometers
  41 ]
  42 */
  43 //]