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Map Matching based on GraphHopper

Build Status

Map matching is the process to match a sequence of real world coordinates into a digital map. Read more at Wikipedia. It can be used for tracking vehicles' GPS information, important for further digital analysis. Or e.g. attaching turn instructions for any recorded GPX route.

Currently this project is under heavy development but produces already good results for various use cases. Let us know if not and create an issue!

See the demo in action (black is GPS track, green is matched result):

map-matching-example

License

Apache License 2.0

Discussion

Discussion happens here.

Installation and Usage

Java 8 and Maven >=3.3 are required. For the 'core' module Java 7 is sufficient.

Then you need to import the area you want to do map-matching on:

git checkout [stable-branch] # optional
./map-matching.sh action=import datasource=./some-dir/osm-file.pbf vehicle=car

As an example you use datasource=./map-data/leipzig_germany.osm.pbf as road network base or any other pbf or xml from here.

The optional parameter vehicle defines the routing profile like car, bike, motorcycle or foot. You can also provide a comma separated list. For all supported values see the variables in the FlagEncoderFactory of GraphHopper.

If you have already imported a datasource with a specific profile, you need to remove the folder graph-cache in your map-matching root directory.

Now you can do these matches:

./map-matching.sh action=match gpx=./some-dir/*.gpx

As example use gpx=./matching-core/src/test/resources/*.gpx or one specific gpx file.

Possible arguments are:

instructions=de             # default=, type=String, if an country-iso-code (like en or de) is specified turn instructions are included in the output, leave empty or default to avoid this
gps_accuracy=15              # default=15, type=int, unit=meter, the precision of the used device

This will produce gpx results similar named as the input files.

UI and matching Service

Start via:

./map-matching.sh action=start-server

Access the simple UI via localhost:8989.

You can post GPX files and get back snapped results as GPX or as compatible GraphHopper JSON. An example curl request is:

curl -XPOST -H "Content-Type: application/gpx+xml" -d @/path/to/gpx/file.gpx "localhost:8989/match?vehicle=car&type=json"

Development tools

Determine the maximum bounds of one or more GPX file:

./map-matching.sh action=getbounds gpx=./track-data/.*gpx

Java usage

Or use this Java snippet:

// import OpenStreetMap data
GraphHopper hopper = new GraphHopper();
hopper.setOSMFile("./map-data/leipzig_germany.osm.pbf");
hopper.setGraphHopperLocation("./target/mapmatchingtest");
CarFlagEncoder encoder = new CarFlagEncoder();
hopper.setEncodingManager(new EncodingManager(encoder));
hopper.getCHFactoryDecorator().setEnabled(false);
hopper.importOrLoad();

// create MapMatching object, can and should be shared accross threads

GraphHopperStorage graph = hopper.getGraphHopperStorage();
LocationIndexMatch locationIndex = new LocationIndexMatch(graph,
                (LocationIndexTree) hopper.getLocationIndex());
MapMatching mapMatching = new MapMatching(graph, locationIndex, encoder);

// do the actual matching, get the GPX entries from a file or via stream
List<GPXEntry> inputGPXEntries = new GPXFile().doImport("nice.gpx").getEntries();
MatchResult mr = mapMatching.doWork(inputGPXEntries);

// return GraphHopper edges with all associated GPX entries
List<EdgeMatch> matches = mr.getEdgeMatches();
// now do something with the edges like storing the edgeIds or doing fetchWayGeometry etc
matches.get(0).getEdgeState();

with this maven dependency:

<dependency>
    <groupId>com.graphhopper</groupId>
    <artifactId>map-matching</artifactId>
    <!-- or 0.9-SNAPSHOT for the unstable -->
    <version>0.8.2</version>
</dependency>

Note

Note that the edge and node IDs from GraphHopper will change for different PBF files, like when updating the OSM data.

About

See this project from Stefan which is used in combination with the GraphHopper routing engine and is used as the algorithmic approach now. Before it was this faster but more heuristic approach.