Mapbox Vector Tiles API

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Documentation

This API produces Mapbox vector tiles, which are used by eg. Digitransit-ui to show information about public transit entities on the map.

The tiles can be fetched from /otp/routers/{routerId}/vectorTiles/{layers}/{z}/{x}/{y}.pbf, where layers is a comma separated list of layer names from the configuration.

Translatable fields in the tiles are translated based on the accept-language header in requests. Currently, only the language with the highest priority from the header is used.

Configuration

To enable this you need to add the feature SandboxAPIMapboxVectorTilesApi in otp-config.json.

The feature must be configured in router-config.json as follows

{
  "vectorTileLayers": [
    {
      "name": "stops",
      "type": "Stop",
      "mapper": "Digitransit",
      "maxZoom": 20,
      "minZoom": 14,
      "cacheMaxSeconds": 600
    },
    {
      "name": "stations",
      "type": "Station",
      "mapper": "Digitransit",
      "maxZoom": 20,
      "minZoom": 12,
      "cacheMaxSeconds": 600
    },
    // all rental places: stations and free-floating vehicles
    {
      "name": "citybikes",
      "type": "VehicleRental",
      "mapper": "Digitransit",
      "maxZoom": 20,
      "minZoom": 14,
      "cacheMaxSeconds": 60,
      "expansionFactor": 0.25
    },
    // just free-floating vehicles
    {
      "name": "rentalVehicles",
      "type": "VehicleRentalVehicle",
      "mapper": "DigitransitRealtime",
      "maxZoom": 20,
      "minZoom": 14,
      "cacheMaxSeconds": 60
    },
    // just rental stations
    {
      "name": "rentalStations",
      "type": "VehicleRentalStation",
      "mapper": "Digitransit",
      "maxZoom": 20,
      "minZoom": 14,
      "cacheMaxSeconds": 600
    },
    // Contains just stations and realtime information for them
    {
      "name": "realtimeRentalStations",
      "type": "VehicleRentalStation",
      "mapper": "DigitransitRealtime",
      "maxZoom": 20,
      "minZoom": 14,
      "cacheMaxSeconds": 60
    },
    // This exists for backwards compatibility. At some point, we might want
    // to add a new realtime parking mapper with better translation support
    // and less unnecessary fields.
    {
      "name": "stadtnaviVehicleParking",
      "type": "VehicleParking",
      "mapper": "Stadtnavi",
      "maxZoom": 20,
      "minZoom": 14,
      "cacheMaxSeconds": 60,
      "expansionFactor": 0.25
    },
    // no realtime, translatable fields are translated based on accept-language header
    // and contains less fields than the Stadtnavi mapper
    {
      "name": "vehicleParking",
      "type": "VehicleParking",
      "mapper": "Digitransit",
      "maxZoom": 20,
      "minZoom": 14,
      "cacheMaxSeconds": 600,
      "expansionFactor": 0.25
    },
    {
      "name": "vehicleParkingGroups",
      "type": "VehicleParkingGroup",
      "mapper": "Digitransit",
      "maxZoom": 17,
      "minZoom": 14,
      "cacheMaxSeconds": 600,
      "expansionFactor": 0.25
    }
  ]
}

For each layer, the configuration includes:

Extending

If more generic layers are created for this API, it should be moved out from the sandbox, into the core code, with potentially leaving specific property mappers in place.

Creating a new layer

In order to create a new type of layer, you need to create a new class extending LayerBuilder<T>. You need to implement two methods, List<Geometry> getGeometries(Envelope query), which returns a list of geometries, with an object of type T as their userData in the geometry, and double getExpansionFactor(), which describes how much information outside the tile bounds should be included. This layer then needs to be added into VectorTilesResource.layers, with a new LayerType enum as the key, and the class constructor as the value.

A new mapper needs to be added every time a new layer is added. See below for information.

Creating a new mapper

The mapping contains information of what data to include in the vector tiles. The mappers are defined per layer.

In order to create a new mapper for a layer, you need to create a new class extending PropertyMapper<T>. In that class, you need to implement the method Collection<T2<String, Object>> map(T input). The type T is dependent on the layer for which you implement the mapper for. It needs to return a list of attributes, as key-value pairs which will be written into the vector tile.

The mapper needs to be added to the mappers map in the layer, with a new MapperType enum as the key, and a function to create the mapper, with a Graph object as a parameter, as the value.

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