Sandwych.MapMatchingKit is a GPS map-matching solution for .NET platform.
This library is ported from the Barefoot project which developed in Java.
From Wikipedia:
Map matching is the problem of how to match recorded geographic coordinates to a logical model of the real world, typically using some form of Geographic Information System. The most common approach is to take recorded, serial location points (e.g. from GPS) and relate them to edges in an existing street graph (network), usually in a sorted list representing the travel of a user or vehicle. Matching observations to a logical model in this way has applications in satellite navigation, GPS tracking of freight, and transportation engineering.
- Sandwych.Hmm: A general purpose utility library implements Hidden Markov Models (HMM) for time-inhomogeneous Markov processes for .NET.
Alpha - Basic functions works.
The API can and will change frequently, do not use it for production.
- Microsoft Visual Studio 2017: This project is written in C# 7.2 using Microsoft Visual Studio 2017 Community Edition Version 15.5.
- DocFX to generate API documents (Optional)
- .NET Standard 1.6
- .NET Framework 4.5
Sandwych.MapMatchingKit can be installed from NuGet.
| Field | Type | Description |
|---|---|---|
| Id | long | The unique ID of road line |
| Source | long | Starting vertex ID of the road line |
| Target | long | Ending vertex ID of the road line |
| Oneway | bool | Indicates the road is a one way road or not |
| Oneway | bool | Indicates the road is a one way road or not |
| Type | short | Indicates the type of the road (Optional) |
| Priority | float | Road priority factor, which is greater or equal than one (default is 1.0) |
| MaxForwardSpeed | float | Maximum speed limit for passing this road from source to target (default is 120.0km/h) |
| MaxBackwardSpeed | float | Maximum speed limit for passing this road from target to source (default is 120.0km/h) |
| Length | float | Length of road geometry in meters, can be computed if not provided |
| Geometry | ILineString | An object of ILineString to represents the road. |
| Field | Type | Description |
|---|---|---|
| Id | long | The unique ID of the GPS point |
| Time | DateTimeOffset | The timestamp of the GPS point |
| Coordinate | Coordinate2D | Longtitude and latitude of the GPS point |
See the directory example/Sandwych.MapMatchingKit.Examples.HelloWorldApp for a fully executable map-matching example.
var spatial = new GeographySpatialOperation();
var mapBuilder = new RoadMapBuilder(spatial);
var roads = //load your road map
var map = mapBuilder.AddRoads(roads).Build();
var router = new DijkstraRouter<Road, RoadPoint>();
var matcher = new Matcher(map, router, Costs.TimePriorityCost, spatial);
var kstate = new MatcherKState();
//Do the map-matching iteration
foreach (var sample in samples)
{
var vector = matcher.Execute(kstate.Vector(), kstate.Sample, sample);
kstate.Update(vector, sample);
}
//Fetching map-matching results and accessing them
var candidatesSequence = kstate.Sequence();
foreach (var cand in candidatesSequence)
{
var roadId = cand.Point.Edge.RoadInfo.Id; // original road id
var heading = cand.Point.Edge.Headeing; // heading
var coord = cand.Point.Coordinate; // GPS position (on the road)
if (cand.HasTransition)
{
var geom = cand.Transition.Route.ToGeometry(); // path geometry(LineString) from last matching candidate
var edges = cand.Transition.Route.Edges // Road segments between two GPS position
}
}// Create initial (empty) state memory
var kstate = new MatcherKState();
// Iterate over sequence (stream) of samples
foreach (var sample in samples)
{
// Execute matcher with single sample and update state memory
var vector = kstate.Vector();
vector = matcher.Execute(vector, kstate.Sample, sample);
kstate.Update(vector, sample);
// Access map matching result: estimate for most recent sample
var estimated = kstate.Estimate();
Console.WriteLine("RoadID={0}", estimated.Point.Edge.RoadInfo.Id); // The id of the road in your map
}- Copyright 2015-2017 BMW Car IT GmbH
- Copyright 2017-2018 Wei "oldrev" Li and Contributors
This library is licensed under the Apache 2.0 license.
Contributions are always welcome! For bug reports, please create an issue.
For code contributions (e.g. new features or bugfixes), please create a pull request.
All honors belongs to the original Barefoot developed by BMW Car IT GmbH: https://github.com/bmwcarit/barefoot
- "hmm-lib" from BMW Car IT GmbH: https://github.com/bmwcarit/hmm-lib
- "GeographicLib" from Charles Karney: https://github.com/oldrev/GeographicLib
- "Nito.Collections.Deque" from Stephen Cleary: https://github.com/StephenCleary/Deque
- "NetTopologySuite & ProjNET4GeoAPI" from NetTopologySuite Project: https://github.com/NetTopologySuite
- PriorityQueue class from Rx.NET Project: https://github.com/Reactive-Extensions/Rx.NET
- The UBODT(upper-bounded origin destination table) algroithm from Can Yang: https://github.com/cyang-kth/fmm
- RBush - The R-Tree spatial index implementation from viceroypenguin: https://github.com/viceroypenguin/RBush
- QuickGraph from Peli: https://github.com/oldrev/Sandwych.QuickGraph