| // Boost.Geometry (aka GGL, Generic Geometry Library) |
| // QuickBook Example |
| |
| // Copyright (c) 2011 Barend Gehrels, Amsterdam, the Netherlands. |
| |
| // Use, modification and distribution is subject to the Boost Software License, |
| // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt) |
| |
| //[area_with_strategy |
| //` Calculate the area of a polygon |
| |
| #include <iostream> |
| |
| #include <boost/geometry.hpp> |
| #include <boost/geometry/geometries/point_xy.hpp> |
| #include <boost/geometry/geometries/polygon.hpp> |
| #include <boost/geometry/domains/gis/io/wkt/wkt.hpp> |
| |
| namespace bg = boost::geometry; /*< Convenient namespace alias >*/ |
| |
| int main() |
| { |
| // Calculate the area of a cartesian polygon |
| bg::model::polygon<bg::model::d2::point_xy<double> > poly; |
| bg::read_wkt("POLYGON((0 0,0 7,4 2,2 0,0 0))", poly); |
| double area = bg::area(poly); |
| std::cout << "Area: " << area << std::endl; |
| |
| // Calculate the area of a spherical polygon (for latitude: 0 at equator) |
| bg::model::polygon<bg::model::point<float, 2, bg::cs::spherical_equatorial<bg::degree> > > sph_poly; |
| bg::read_wkt("POLYGON((0 0,0 45,45 0,0 0))", sph_poly); |
| area = bg::area(sph_poly); |
| std::cout << "Area: " << area << std::endl; |
| |
| return 0; |
| } |
| |
| //] |
| |
| |
| //[area_with_strategy_output |
| /*` |
| Output: |
| [pre |
| Area: 16 |
| Area: 0.339837 |
| ] |
| */ |
| //] |