ceph/src/boost/libs/geometry/doc/index/src/examples/rtree/variants_map.cpp

   1 // Boost.Geometry Index
   2 //
   3 // Quickbook Examples
   4 //
   5 // Copyright (c) 2011-2013 Adam Wulkiewicz, Lodz, Poland.
   6 //
   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
  11 //[rtree_variants_map
  12
  13 #include <boost/geometry.hpp>
  14 #include <boost/geometry/geometries/point.hpp>
  15 #include <boost/geometry/geometries/box.hpp>
  16 #include <boost/geometry/geometries/polygon.hpp>
  17 #include <boost/geometry/geometries/ring.hpp>
  18 #include <boost/geometry/geometries/linestring.hpp>
  19
  20 #include <boost/geometry/index/rtree.hpp>
  21
  22 #include <cmath>
  23 #include <vector>
  24 #include <map>
  25 #include <iostream>
  26 #include <boost/foreach.hpp>
  27 #include <boost/variant.hpp>
  28
  29 namespace bg = boost::geometry;
  30 namespace bgi = boost::geometry::index;
  31
  32 typedef bg::model::point<float, 2, bg::cs::cartesian> point;
  33 typedef bg::model::box<point> box;
  34 typedef bg::model::polygon<point, false, false> polygon; // ccw, open polygon
  35 typedef bg::model::ring<point, false, false> ring; // ccw, open ring
  36 typedef bg::model::linestring<point> linestring;
  37 typedef boost::variant<polygon, ring, linestring> geometry;
  38
  39 typedef std::map<unsigned, geometry> map;
  40 typedef std::pair<box, map::iterator> value;
  41
  42 template <class Container>
  43 void fill(unsigned i, Container & container)
  44 {
  45     for ( float a = 0 ; a < 6.28316f ; a += 1.04720f )
  46     {
  47         float x = i + int(10*::cos(a))*0.1f;
  48         float y = i + int(10*::sin(a))*0.1f;
  49         container.push_back(point(x, y));
  50     }
  51 }
  52
  53 struct print_visitor : public boost::static_visitor<>
  54 {
  55     void operator()(polygon const& g) const { std::cout << bg::wkt<polygon>(g) << std::endl; }
  56     void operator()(ring const& g) const { std::cout << bg::wkt<ring>(g) << std::endl; }
  57     void operator()(linestring const& g) const { std::cout << bg::wkt<linestring>(g) << std::endl; }
  58 };
  59
  60 struct envelope_visitor : public boost::static_visitor<box>
  61 {
  62     box operator()(polygon const& g) const { return bg::return_envelope<box>(g); }
  63     box operator()(ring const& g) const { return bg::return_envelope<box>(g); }
  64     box operator()(linestring const& g) const { return bg::return_envelope<box>(g); }
  65 };
  66
  67
  68 int main()
  69 {
  70     // geometries container
  71     map geometries;
  72
  73     // create some geometries
  74     for ( unsigned i = 0 ; i < 10 ; ++i )
  75     {
  76         unsigned c = rand() % 3;
  77
  78         if ( 0 == c )
  79         {
  80             // create polygon
  81             polygon p;
  82             fill(i, p.outer());
  83             geometries.insert(std::make_pair(i, geometry(p)));
  84         }
  85         else if ( 1 == c )
  86         {
  87             // create ring
  88             ring r;
  89             fill(i, r);
  90             geometries.insert(std::make_pair(i, geometry(r)));
  91         }
  92         else if ( 2 == c )
  93         {
  94             // create linestring
  95             linestring l;
  96             fill(i, l);
  97             geometries.insert(std::make_pair(i, geometry(l)));
  98         }
  99     }
 100
 101     // display geometries
 102     std::cout << "generated geometries:" << std::endl;
 103     BOOST_FOREACH(map::value_type const& p, geometries)
 104         boost::apply_visitor(print_visitor(), p.second);
 105
 106     // create the rtree using default constructor
 107     bgi::rtree< value, bgi::quadratic<16, 4> > rtree;
 108
 109     // fill the spatial index
 110     for ( map::iterator it = geometries.begin() ; it != geometries.end() ; ++it )
 111     {
 112         // calculate polygon bounding box
 113         box b = boost::apply_visitor(envelope_visitor(), it->second);
 114         // insert new value
 115         rtree.insert(std::make_pair(b, it));
 116     }
 117
 118     // find values intersecting some area defined by a box
 119     box query_box(point(0, 0), point(5, 5));
 120     std::vector<value> result_s;
 121     rtree.query(bgi::intersects(query_box), std::back_inserter(result_s));
 122
 123     // find 5 nearest values to a point
 124     std::vector<value> result_n;
 125     rtree.query(bgi::nearest(point(0, 0), 5), std::back_inserter(result_n));
 126
 127     // note: in Boost.Geometry the WKT representation of a box is polygon
 128
 129     // note: the values store the bounding boxes of geometries
 130     // the geometries aren't used for querying but are printed
 131
 132     // display results
 133     std::cout << "spatial query box:" << std::endl;
 134     std::cout << bg::wkt<box>(query_box) << std::endl;
 135     std::cout << "spatial query result:" << std::endl;
 136     BOOST_FOREACH(value const& v, result_s)
 137         boost::apply_visitor(print_visitor(), v.second->second);
 138
 139     std::cout << "knn query point:" << std::endl;
 140     std::cout << bg::wkt<point>(point(0, 0)) << std::endl;
 141     std::cout << "knn query result:" << std::endl;
 142     BOOST_FOREACH(value const& v, result_n)
 143         boost::apply_visitor(print_visitor(), v.second->second);
 144
 145     return 0;
 146 }
 147
 148 //]