osrm-backend/plugins/map_matching.hpp
2015-03-03 00:48:56 +01:00

262 lines
9.4 KiB
C++

/*
open source routing machine
Copyright (C) Dennis Luxen, others 2010
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU AFFERO General Public License as published by
the Free Software Foundation; either version 3 of the License, or
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
or see http://www.gnu.org/licenses/agpl.txt.
*/
#ifndef MAP_MATCHING_PLUGIN_H
#define MAP_MATCHING_PLUGIN_H
#include "plugin_base.hpp"
#include "../algorithms/bayes_classifier.hpp"
#include "../algorithms/object_encoder.hpp"
#include "../util/integer_range.hpp"
#include "../data_structures/search_engine.hpp"
#include "../routing_algorithms/map_matching.hpp"
#include "../util/compute_angle.hpp"
#include "../util/simple_logger.hpp"
#include "../util/string_util.hpp"
#include "../descriptors/descriptor_base.hpp"
#include "../descriptors/gpx_descriptor.hpp"
#include "../descriptors/json_descriptor.hpp"
#include <cstdlib>
#include <algorithm>
#include <memory>
#include <string>
#include <vector>
template <class DataFacadeT> class MapMatchingPlugin : public BasePlugin
{
private:
std::unordered_map<std::string, unsigned> descriptor_table;
std::shared_ptr<SearchEngine<DataFacadeT>> search_engine_ptr;
using ClassifierT = BayesClassifier<LaplaceDistribution, LaplaceDistribution, double>;
using TraceClassification = ClassifierT::ClassificationT;
public:
MapMatchingPlugin(DataFacadeT *facade)
: descriptor_string("match")
, facade(facade)
// the values where derived from fitting a laplace distribution
// to the values of manually classified traces
, classifier(LaplaceDistribution(0.0057154021891018675, 0.020294704891166186),
LaplaceDistribution(0.11467696742821254, 0.49918444000368756),
0.7977883096366508) // valid apriori probability
{
descriptor_table.emplace("json", 0);
descriptor_table.emplace("gpx", 1);
// descriptor_table.emplace("geojson", 2);
//
search_engine_ptr = std::make_shared<SearchEngine<DataFacadeT>>(facade);
}
virtual ~MapMatchingPlugin() { search_engine_ptr.reset(); }
const std::string GetDescriptor() const final { return descriptor_string; }
TraceClassification classify(float trace_length, float matched_length, int removed_points) const
{
double distance_feature = -std::log(trace_length) + std::log(matched_length);
// matched to the same point
if (!std::isfinite(distance_feature))
{
return std::make_pair(ClassifierT::ClassLabel::NEGATIVE, 1.0);
}
auto label_with_confidence = classifier.classify(distance_feature);
// "second stage classifier": if we need to remove points there is something fishy
if (removed_points > 0)
{
return std::make_pair(ClassifierT::ClassLabel::NEGATIVE, 1.0);
}
return label_with_confidence;
}
bool get_candiates(const std::vector<FixedPointCoordinate>& input_coords, double& trace_length, Matching::CandidateLists& candidates_lists)
{
double last_distance = coordinate_calculation::great_circle_distance(
input_coords[0],
input_coords[1]);
trace_length = 0;
for (const auto current_coordinate : osrm::irange<std::size_t>(0, input_coords.size()))
{
bool allow_uturn = false;
if (0 < current_coordinate)
{
last_distance = coordinate_calculation::great_circle_distance(
input_coords[current_coordinate - 1],
input_coords[current_coordinate]);
trace_length += last_distance;
}
if (input_coords.size()-1 > current_coordinate && 0 < current_coordinate)
{
double turn_angle = ComputeAngle::OfThreeFixedPointCoordinates(
input_coords[current_coordinate-1],
input_coords[current_coordinate],
input_coords[current_coordinate+1]);
// sharp turns indicate a possible uturn
if (turn_angle < 100.0 || turn_angle > 260.0)
{
allow_uturn = true;
}
}
std::vector<std::pair<PhantomNode, double>> candidates;
if (!facade->IncrementalFindPhantomNodeForCoordinateWithMaxDistance(
input_coords[current_coordinate],
candidates,
last_distance/2.0,
5,
20))
{
return false;
}
if (allow_uturn)
{
candidates_lists.push_back(candidates);
}
else
{
unsigned compact_size = candidates.size();
for (const auto i : osrm::irange(0u, compact_size))
{
// Split edge if it is bidirectional and append reverse direction to end of list
if (candidates[i].first.forward_node_id != SPECIAL_NODEID
&& candidates[i].first.reverse_node_id != SPECIAL_NODEID)
{
PhantomNode reverse_node(candidates[i].first);
reverse_node.forward_node_id = SPECIAL_NODEID;
candidates.push_back(std::make_pair(reverse_node, candidates[i].second));
candidates[i].first.reverse_node_id = SPECIAL_NODEID;
}
}
candidates_lists.push_back(candidates);
}
}
return true;
}
int HandleRequest(const RouteParameters &route_parameters, JSON::Object &json_result) final
{
// check number of parameters
if (!check_all_coordinates(route_parameters.coordinates))
{
return 400;
}
double trace_length;
Matching::CandidateLists candidates_lists;
const auto& input_coords = route_parameters.coordinates;
bool found_candidates = get_candiates(input_coords, trace_length, candidates_lists);
if (!found_candidates)
{
return 400;
}
// call the actual map matching
JSON::Object debug_info;
float matched_length;
std::vector<PhantomNode> matched_nodes;
search_engine_ptr->map_matching(candidates_lists, input_coords, matched_nodes, matched_length, debug_info);
// classify result
TraceClassification classification = classify(trace_length, matched_length, input_coords.size() - matched_nodes.size());
if (classification.first == ClassifierT::ClassLabel::POSITIVE)
{
json_result.values["confidence"] = classification.second;
}
else
{
json_result.values["confidence"] = 1-classification.second;
}
// run shortest path routing to obtain geometry
InternalRouteResult raw_route;
PhantomNodes current_phantom_node_pair;
for (unsigned i = 0; i < matched_nodes.size() - 1; ++i)
{
current_phantom_node_pair.source_phantom = matched_nodes[i];
current_phantom_node_pair.target_phantom = matched_nodes[i + 1];
raw_route.segment_end_coordinates.emplace_back(current_phantom_node_pair);
}
if (2 > matched_nodes.size())
{
return 400;
}
search_engine_ptr->shortest_path(
raw_route.segment_end_coordinates,
std::vector<bool>(raw_route.segment_end_coordinates.size(), true),
raw_route);
DescriptorConfig descriptor_config;
auto iter = descriptor_table.find(route_parameters.output_format);
unsigned descriptor_type = (iter != descriptor_table.end() ? iter->second : 0);
descriptor_config.zoom_level = route_parameters.zoom_level;
descriptor_config.instructions = route_parameters.print_instructions;
descriptor_config.geometry = route_parameters.geometry;
descriptor_config.encode_geometry = route_parameters.compression;
std::shared_ptr<BaseDescriptor<DataFacadeT>> descriptor;
switch (descriptor_type)
{
// case 0:
// descriptor = std::make_shared<JSONDescriptor<DataFacadeT>>();
// break;
case 1:
descriptor = std::make_shared<GPXDescriptor<DataFacadeT>>(facade);
break;
// case 2:
// descriptor = std::make_shared<GEOJSONDescriptor<DataFacadeT>>();
// break;
default:
descriptor = std::make_shared<JSONDescriptor<DataFacadeT>>(facade);
break;
}
descriptor->SetConfig(descriptor_config);
descriptor->Run(raw_route, json_result);
json_result.values["debug"] = debug_info;
return 200;
}
private:
std::string descriptor_string;
DataFacadeT *facade;
ClassifierT classifier;
};
#endif /* MAP_MATCHING_PLUGIN_H */