Map Matching & Weight Completion service - Java (Springboot) & Python(Flask)

Authors

• Adil Cemalovic
• Christian Damsgaard
• Magnus Lund
• Martin Lønne
• Simon Holst
• Søren Hjorth Boelskifte

MapMatching - Java Springboot

A GraphHopper based map matching service for the aSTEP platform.

The service makes use of the open source GraphHopper routing libraries:

• https://github.com/graphhopper/map-matching
• https://github.com/graphhopper/graphhopper

The project is written in Java and use the Spring Boot web framework.

About the service

The map matching is perfomed based on map data from Open Street Map.

NB! Currently, only trips in the Chinese city Chengdu can be map matched. If you wish to map match another area, fork the project and import a new area as an OSM-file by using GraphHopper's methods.

Integration with aSTEP

This service is implemented as a REST API and can be used freely by all current and future services on the aSTEP platform.

Multiple map matching services already exists on aSTEP. However, this service offers more data as described in the section How to use.

The service has been made in collaboration with another semester group, Group SW505E20, whose service calls the API. Group SW505 have set up a GUI and database in order to make the map matching functionality in this service available on the aSTEP platform:

• aSTEP: https://astep.cs.aau.dk/tool/astep-2020-fall-sw505-test-service.astep-dev.cs.aau.dk

How to use

The service exposes the endpoint /mapmatch which accepts a POST request containing raw GPS points and returns the generated map matched points combined with other data that may be useful. Input and output data are both in JSON format.

Expected input

A list of one or more trips containing a list of one or more raw GPS points. Every GPS point must include a latitude, longitude and timestamp. The format of the expected input can be seen here:

[
  {
    "rawPoints": [
      {
        "latitude": 30.62377,
        "longitude": 104.02045,
        "timestamp": "2020-10-21T11:07:41Z"
      },
      {
        "latitude": 30.62665,
        "longitude": 104.02243,
        "timestamp": "2020-10-21T11:08:43Z"
      },
      {
            ......
            ......
      }
    ]
  },
  {
    "rawPoints": [
      {
            ......
            ......
      }
    ]
  }
]

Output

A list of one or more routes containing a list of edges.

An edge corresponds to a segment consisting of a start and end OSM node in the OSM map, where each node reflects a road intersection. Furthermore, an edge contains a distance, which reflects the length of the edge in meters. It also contains information about the average speed traveled on the edge in meters per second. Finally, each edge belongs to an OSM way, which is represented by a OSM way ID.

A route also has a list of matched points, which is a list of points with a latitude and longitude that are snapped to the edge. Finally, a route also has a total distance in meters, as well as the average speed traveled on the whole route. The format of the output can be seen here:

[
    {
      "edges": [
          {
              "osmWayId": 345684193,
              "startNode": {
                  "osmNodeId": 4972899580,
                  "timestamp": "2020-12-14T10:43:32.733+00:00",
                  "latitude": 30.633103600884308,
                  "longitude": 104.04822928566253
              },
              "endNode": {
                  "osmNodeId": 4972899582,
                  "timestamp": "2020-12-14T10:43:34.303+00:00",
                  "latitude": 30.632922924300797,
                  "longitude": 104.04861261804281
              },
              "distance": 41.818,
              "averageSpeed": 26.62481282559887
          },
          {
            ...
          },
          ...
      ],
      "matchedPoints": [
          {
              "latitude": 30.6330068834206,
              "longitude": 104.04843448621955
          },
          {
            ...
          },
          ...
      ],
      "distance": 622.9006982605781,
      "averageSpeed": 15.192699957575076
    }
]

Please note that data is not saved in this service. The client is responsible for saving the returned result in their own service if necessary.

Running the service locally

Just use Docker! 🐳

A docker file is placed in the root folder of this project. Map your local port to port 5000 of the docker container and call the endpoint at http://localhost:YOURLOCALPORT/mapmath

A number of files containing valid, as well as invalid (for testing purposes), input in JSON are placed in the /files folder and can be used to test the service.

Weight Completion

A Weight Completion service for the aSTEP platform - written in Python / Flask.

The service uses machine learning to fill out missing weights in a road network, for a specified time interval. At the moment, the Weight Completion Service can only do weight completion in the Chinese city, Chengdu.

The graph completion algorithm used in the service is based on the Github repository GraphCompletion, created by Jilin Hu, Chenjuan Guo, Bin Yang and Christian S. Jensen. The algorithm was created as a part of the scientific paper "Stochastic Weight Completion for Road Networks Using Graph Convolutional Networks", which can be found here.

The Flask framework has been used as the web framework in this project.

How to use

Please select a date from the form in the menu. After selecting a date, a specific time interval can be selected. A road network with incomplete weights can be visualized on the map by leaving the checkbox unchecked. If checked, a road network with completed weights will be shown. Two tabs are then presented. The first tab will allow the user to inspect the edges on a map, and the other will show the weights for all edges in a table.

Running the service locally

A requirements-file has been provided in order to set up the correct dependencies. As the code uses old versions of several libraries, please ensure that these versions are correct. If you have trouble installing the requirements file, take a look on the trouble shooting comments in the requirements file.

Furtermore, a docker file has been provided if you wish to run the service inside docker. A docker file is placed in the root folder of this project. Map your local port to port 5000 of the docker container and call the endpoint at http://localhost:YOURLOCALPORT/mapmath