Compute a Route Matrix

You can calculate the distance and duration of a route for multiple origins and destinations by using the ComputeRouteMatrix method of the Routes Preferred API. ComputeRouteMatrix supports both streaming gRPC calls and REST HTTP calls.

Given a list of origin and destination pairs, ComputeRouteMatrix calculates the distance and duration of a route starting at each origin and ending at each destination. Each element of the stream corresponds to the information for a single route.

The ComputeRouteMatrix method has several advantages over the Distance Matrix Service:

  • Streaming allows elements to be returned before the entire matrix has been calculated, lowering latency.
  • ComputeRouteMatrix has fine-grained options for traffic calculation, letting you make quality-latency tradeoff decisions.
  • Requests are run at a higher priority within Google’s infrastructure, which results in higher availability.
  • You can specify heading (direction of travel) and side-of-road information for waypoints.
  • You can request for toll information to be returned, along with route distance and ETA.

Enable the ComputeRouteMatrix method

Before you can use the ComputeRouteMatrix method in your code, you must enable it. For more information on enabling Routes Preferred API methods, see Getting Started.

Use the ComputeRouteMatrix method

The ComputeRouteMatrix method is available through the Routes Preferred v1 endpoint.

See the following documentation for more detailed information:

gRPC: https://developers.google.com/maps/documentation/routes_preferred/reference/rpc/google.maps.routes.v1

REST: https://developers.google.com/maps/documentation/routes_preferred/reference/rest/v1/TopLevel/computeRouteMatrix

The following generic steps describe how to use gRPC to call the ComputeRouteMatrix method:

  1. Check out the necessary protobuffers from the googleapis repository:

    https://github.com/googleapis/googleapis/tree/master/google/maps/routes

    Note that some build systems, such as Go, may automatically do this for you.

  2. Using your preferred language and set of build tools, generate the relevant protobuffer code.

  3. Generate your request. Two required pieces of metadata must be sent with the request:

    • X-Goog-Api-Key must be set to your API key.

    • X-Goog-Fieldmask must be set to a comma separated list of the fields you require from the response. For example, X-Goog-FieldMask: originIndex,destinationIndex,duration,distanceMeters,status. You can use the wildcard character (*) to denote all fields, but that is discouraged. Use the wildcard character to test and understand the API response, but explicitly list the fields you want in the field mask in your production code.

      For more information on how to construct the field mask string, see https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/field_mask.proto. Note that disabling fields you do not need can reduce latency since those fields may require further computation. Your latency will stay stable if you specify the fields you need and new fields that require more computation are added later.

  4. Send your request to routespreferred.googleapis.com:443.You must use the TLS protocol.

For examples of using the ComputeRouteMatrix method, see Computing a Route Matrix (Beta) Examples.

One distinguishing feature of the ComputeRouteMatrix method is that error codes can be returned either for the entire stream or for individual elements. For example, the stream connection returns an error if the request is malformed (for example, it has zero origins). However, if an error applies to just a few elements of the stream (for example, setting an invalid Place ID for an origin), then only the elements affected by the error contain error codes.

The elements returned by the stream are not guaranteed to be returned in any order. Because of this, each element contains an origin_index and a destination_index. For the origins and destinations specified by the request, the route origin is equivalent to origins[origin_index] for a given element and the route destination is is equivalent to destinations[destination_index]. These arrays are zero-indexed. It is important to store the origin and destination list orders.

Calculating toll fees

For information on calculating toll fees, see Calculate toll fees.

For examples of calculating toll fees, see Computing a Route Matrix Examples.