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 //[comparable_distance
11 //` Shows how to efficiently get the closest point
12
13 #include <iostream>
14
15 #include <boost/geometry.hpp>
16 #include <boost/geometry/geometries/point_xy.hpp>
17
18 #include <boost/numeric/conversion/bounds.hpp>
19 #include <boost/foreach.hpp>
20
main()21 int main()
22 {
23 typedef boost::geometry::model::d2::point_xy<double> point_type;
24
25 point_type p(1.4, 2.6);
26
27 std::vector<point_type> v;
28 for (double x = 0.0; x <= 4.0; x++)
29 {
30 for (double y = 0.0; y <= 4.0; y++)
31 {
32 v.push_back(point_type(x, y));
33 }
34 }
35
36 point_type min_p;
37 double min_d = boost::numeric::bounds<double>::highest();
38 BOOST_FOREACH(point_type const& pv, v)
39 {
40 double d = boost::geometry::comparable_distance(p, pv);
41 if (d < min_d)
42 {
43 min_d = d;
44 min_p = pv;
45 }
46 }
47
48 std::cout
49 << "Closest: " << boost::geometry::dsv(min_p) << std::endl
50 << "At: " << boost::geometry::distance(p, min_p) << std::endl;
51
52 return 0;
53 }
54
55 //]
56
57
58 //[comparable_distance_output
59 /*`
60 Output:
61 [pre
62 Closest: (1, 3)
63 At: 0.565685
64 ]
65 */
66 //]
67
68