374 lines
12 KiB
C++
374 lines
12 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
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// Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
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// Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// Example showing Boost.Geometry combined with Boost.Graph, calculating shortest routes
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// input: two WKT's, provided in subfolder data
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// output: text, + an SVG, displayable in e.g. Firefox)
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// Second variant, with bundled properties
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#include <iostream>
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#include <fstream>
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#include <iomanip>
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#include <limits>
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#include <boost/tuple/tuple.hpp>
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#include <boost/foreach.hpp>
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#include <boost/graph/adjacency_list.hpp>
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#include <boost/graph/dijkstra_shortest_paths.hpp>
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#include <boost/geometry/geometry.hpp>
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#include <boost/geometry/geometries/linestring.hpp>
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#include <boost/geometry/io/wkt/read.hpp>
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// For output:
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#include <boost/geometry/io/svg/svg_mapper.hpp>
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// For distance-calculations over the Earth:
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//#include <boost/geometry/extensions/gis/geographic/strategies/andoyer.hpp>
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// Read an ASCII file containing WKT's, fill a vector of tuples
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// The tuples consist of at least <0> a geometry and <1> an identifying string
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template <typename Geometry, typename Tuple, typename Box>
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void read_wkt(std::string const& filename, std::vector<Tuple>& tuples, Box& box)
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{
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std::ifstream cpp_file(filename.c_str());
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if (cpp_file.is_open())
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{
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while (! cpp_file.eof() )
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{
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std::string line;
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std::getline(cpp_file, line);
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Geometry geometry;
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boost::trim(line);
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if (! line.empty() && ! boost::starts_with(line, "#"))
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{
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std::string name;
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// Split at ';', if any
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std::string::size_type pos = line.find(";");
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if (pos != std::string::npos)
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{
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name = line.substr(pos + 1);
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line.erase(pos);
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boost::trim(line);
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boost::trim(name);
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}
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Geometry geometry;
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boost::geometry::read_wkt(line, geometry);
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Tuple tuple(geometry, name);
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tuples.push_back(tuple);
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boost::geometry::expand(box, boost::geometry::return_envelope<Box>(geometry));
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}
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}
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}
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}
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// To calculate distance, declare and construct a strategy with average earth radius
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boost::geometry::strategy::distance::haversine<double> const haversine(6372795.0);
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// Define properties for vertex
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template <typename Point>
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struct bg_vertex_property
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{
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bg_vertex_property()
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{
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boost::geometry::assign_zero(location);
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}
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bg_vertex_property(Point const& loc)
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: location(loc)
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{
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}
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Point location;
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};
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// Define properties for edge
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template <typename Linestring>
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struct bg_edge_property
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{
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bg_edge_property(Linestring const& line)
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: length(boost::geometry::length(line, haversine))
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, m_line(line)
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{
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}
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inline Linestring const& line() const
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{
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return m_line;
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}
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double length;
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private :
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Linestring m_line;
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};
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// Utility function to add a vertex to a graph. It might exist already. Then do not insert,
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// but return vertex descriptor back. It might not exist. Then add it (and return).
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// To efficiently handle this, a std::map is used.
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template <typename M, typename K, typename G>
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inline typename boost::graph_traits<G>::vertex_descriptor find_or_insert(M& map, K const& key, G& graph)
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{
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typename M::const_iterator it = map.find(key);
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if (it == map.end())
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{
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// Add a vertex to the graph
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typename boost::graph_traits<G>::vertex_descriptor new_vertex
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= boost::add_vertex(bg_vertex_property<typename M::key_type>(key), graph);
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// Add to the map, using POINT as key
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map[key] = new_vertex;
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return new_vertex;
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}
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return it->second;
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}
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template
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<
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typename Graph,
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typename RoadTupleVector,
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typename CityTupleVector
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>
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void add_roads_and_connect_cities(Graph& graph,
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RoadTupleVector const& roads,
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CityTupleVector& cities)
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{
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typedef typename boost::range_value<RoadTupleVector>::type road_type;
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typedef typename boost::tuples::element<0, road_type>::type line_type;
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typedef typename boost::geometry::point_type<line_type>::type point_type;
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typedef typename boost::graph_traits<Graph>::vertex_descriptor vertex_type;
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// Define a map to be used during graph filling
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// Maps from point to vertex-id's
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typedef std::map<point_type, vertex_type, boost::geometry::less<point_type> > map_type;
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map_type map;
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// Fill the graph
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BOOST_FOREACH(road_type const& road, roads)
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{
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line_type const& line = road.template get<0>();
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// Find or add begin/end point of these line
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vertex_type from = find_or_insert(map, line.front(), graph);
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vertex_type to = find_or_insert(map, line.back(), graph);
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boost::add_edge(from, to, bg_edge_property<line_type>(line), graph);
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}
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// Find nearest graph vertex for each city, using the map
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typedef typename boost::range_value<CityTupleVector>::type city_type;
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BOOST_FOREACH(city_type& city, cities)
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{
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double min_distance = 1e300;
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for(typename map_type::const_iterator it = map.begin(); it != map.end(); ++it)
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{
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double dist = boost::geometry::distance(it->first, city.template get<0>());
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if (dist < min_distance)
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{
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min_distance = dist;
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// Set the vertex
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city.template get<2>() = it->second;
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}
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}
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}
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}
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template <typename Graph, typename Route>
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inline void add_edge_to_route(Graph const& graph,
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typename boost::graph_traits<Graph>::vertex_descriptor vertex1,
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typename boost::graph_traits<Graph>::vertex_descriptor vertex2,
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Route& route)
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{
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std::pair
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<
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typename boost::graph_traits<Graph>::edge_descriptor,
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bool
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> opt_edge = boost::edge(vertex1, vertex2, graph);
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if (opt_edge.second)
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{
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// Get properties of edge and of vertex
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bg_edge_property<Route> const& edge_prop = graph[opt_edge.first];
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bg_vertex_property
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<
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typename boost::geometry::point_type<Route>::type
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> const& vertex_prop = graph[vertex2];
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// Depending on how edge connects to vertex, copy it forward or backward
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if (boost::geometry::equals(edge_prop.line().front(), vertex_prop.location))
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{
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std::copy(edge_prop.line().begin(), edge_prop.line().end(),
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std::back_inserter(route));
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}
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else
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{
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std::reverse_copy(edge_prop.line().begin(), edge_prop.line().end(),
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std::back_inserter(route));
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}
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}
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}
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template <typename Graph, typename Route>
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inline void build_route(Graph const& graph,
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std::vector<typename boost::graph_traits<Graph>::vertex_descriptor> const& predecessors,
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typename boost::graph_traits<Graph>::vertex_descriptor vertex1,
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typename boost::graph_traits<Graph>::vertex_descriptor vertex2,
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Route& route)
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{
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typedef typename boost::graph_traits<Graph>::vertex_descriptor vertex_type;
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vertex_type pred = predecessors[vertex2];
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add_edge_to_route(graph, vertex2, pred, route);
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while (pred != vertex1)
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{
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add_edge_to_route(graph, predecessors[pred], pred, route);
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pred = predecessors[pred];
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}
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}
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int main()
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{
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// Define a point in the Geographic coordinate system (currently spherical-equatorial)
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// (geographic calculations are in an extension; for sample it makes no difference)
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typedef boost::geometry::model::point
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<
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double, 2, boost::geometry::cs::spherical_equatorial<boost::geometry::degree>
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> point_type;
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typedef boost::geometry::model::linestring<point_type> line_type;
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// Define the graph, lateron containing the road network
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// With this, specify bundled properties for vertex and edge,
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// as in http://www.boost.org/doc/libs/1_43_0/libs/graph/doc/bundles.html
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typedef boost::adjacency_list
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<
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boost::vecS, boost::vecS, boost::undirectedS
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, bg_vertex_property<point_type> // bundled
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, bg_edge_property<line_type>
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> graph_type;
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typedef boost::graph_traits<graph_type>::vertex_descriptor vertex_type;
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// Init a bounding box, lateron used to define SVG map
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boost::geometry::model::box<point_type> box;
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boost::geometry::assign_inverse(box);
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graph_type graph;
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// Read the cities
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typedef boost::tuple<point_type, std::string, vertex_type> city_type;
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std::vector<city_type> cities;
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read_wkt<point_type>("data/cities.wkt", cities, box);
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// Read the road network
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typedef boost::tuple<line_type, std::string> road_type;
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std::vector<road_type> roads;
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read_wkt<line_type>("data/roads.wkt", roads, box);
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// Add roads and connect cities
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add_roads_and_connect_cities(graph, roads, cities);
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double const km = 1000.0;
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std::cout << "distances, all in KM" << std::endl
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<< std::fixed << std::setprecision(0);
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// Main functionality: calculate shortest routes from/to all cities
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// For the first one, the complete route is stored as a linestring
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bool first = true;
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line_type route;
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int const n = boost::num_vertices(graph);
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BOOST_FOREACH(city_type const& city1, cities)
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{
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std::vector<vertex_type> predecessors(n);
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std::vector<double> costs(n);
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// Call Dijkstra (without named-parameter to be compatible with all VC)
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boost::dijkstra_shortest_paths(graph, city1.get<2>(),
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&predecessors[0], &costs[0],
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boost::get(&bg_edge_property<line_type>::length, graph),
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boost::get(boost::vertex_index, graph),
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std::less<double>(), std::plus<double>(),
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(std::numeric_limits<double>::max)(), double(),
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boost::dijkstra_visitor<boost::null_visitor>());
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BOOST_FOREACH(city_type const& city2, cities)
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{
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if (! boost::equals(city1.get<1>(), city2.get<1>()))
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{
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double distance = costs[city2.get<2>()] / km;
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double acof = boost::geometry::distance(city1.get<0>(), city2.get<0>(), haversine) / km;
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std::cout
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<< std::setiosflags (std::ios_base::left) << std::setw(15)
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<< city1.get<1>() << " - "
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<< std::setiosflags (std::ios_base::left) << std::setw(15)
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<< city2.get<1>()
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<< " -> through the air: " << std::setw(4) << acof
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<< " , over the road: " << std::setw(4) << distance
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<< std::endl;
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if (first)
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{
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build_route(graph, predecessors,
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city1.get<2>(), city2.get<2>(),
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route);
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first = false;
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}
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}
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}
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}
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#if defined(HAVE_SVG)
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// Create the SVG
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std::ofstream stream("routes.svg");
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boost::geometry::svg_mapper<point_type> mapper(stream, 600, 600);
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// Map roads
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BOOST_FOREACH(road_type const& road, roads)
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{
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mapper.add(road.get<0>());
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}
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BOOST_FOREACH(road_type const& road, roads)
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{
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mapper.map(road.get<0>(),
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"stroke:rgb(128,128,128);stroke-width:1");
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}
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mapper.map(route,
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"stroke:rgb(0, 255, 0);stroke-width:6;opacity:0.5");
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// Map cities
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BOOST_FOREACH(city_type const& city, cities)
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{
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mapper.map(city.get<0>(),
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"fill:rgb(255,255,0);stroke:rgb(0,0,0);stroke-width:1");
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mapper.text(city.get<0>(), city.get<1>(),
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"fill:rgb(0,0,0);font-family:Arial;font-size:10px", 5, 5);
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}
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#endif
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return 0;
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}
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