...one of the most highly
regarded and expertly designed C++ library projects in the
world.

— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards

Get coordinate value of a geometry (usually a point)

The free functions **get** and **set** are two of the most important functions of
Boost.Geometry, both within the library, as also for the library user.
With these two functions you normally get and set coordinate values from
and for a point, box, segment or sphere.

template<std::size_t Dimension, typename Geometry> constexpr coordinate_type<Geometry>::type get(Geometry const & geometry)

Type |
Concept |
Name |
Description |
---|---|---|---|

Dimension |
Dimension, this template parameter is required. Should contain [0 .. n-1] for an n-dimensional geometry |
- |
Must be specified |

Geometry const & |
Any type fulfilling a Geometry Concept (usually a Point Concept) |
geometry |
A model of the specified concept (usually a point) |

The coordinate value of specified dimension of specified geometry

Either

`#include <boost/geometry.hpp>`

Or

`#include <boost/geometry/core/access.hpp>`

Case |
Behavior |
---|---|

Point |
Returns the coordinate of a point |

Circle or Sphere |
Returns the coordinate of the center of a circle or sphere (currently in an extension) |

Spherical |
Returns the coordinate of a point, in either Radian's or Degree's, depending on specified units |

Constant

Get the coordinate of a point

#include <iostream> #include <boost/geometry.hpp> #include <boost/geometry/geometries/point_xy.hpp> namespace bg = boost::geometry; int main() { bg::model::d2::point_xy<double> point(1, 2); double x = bg::get<0>(point); double y = bg::get<1>(point); std::cout << "x=" << x << " y=" << y << std::endl; return 0; }

Output:

x=1 y=2