Check VPS availability at the device's current location

The Geospatial API uses a combination of VPS and GPS data to generate high-accuracy Geospatial poses. The API can be used in any place where the device is able to determine its location:

• In areas with low GPS accuracy, such as indoor spaces and dense urban environments, the API will rely on VPS coverage to generate high-accuracy poses.
• In outdoor environments with few or no overhead obstructions, the Geospatial API may be able to use available GPS location data to generate Geospatial poses with high accuracy.

You can determine VPS availability at a given horizontal position before the AR session starts and use it to create more specific experiences — for example, to present an "Enter AR" button only when VPS is available.

Enable the ARCore API

Your app must enable the ARCore API to check VPS availability.

Once the ARCore API is enabled, you can check VPS availability without:

• A current running Session (before calling Session.resume()).
• Setting a GeospatialMode.

Check VPS availability in your app

The Geospatial API can be used in any place where the device is able to determine its location. If your AR experience hinges on VPS coverage, you can use Session.checkVpsAvailabilityAsync() to obtain a VpsAvailabilityFuture, an asynchronous task that checks the VPS availability at a given horizontal position. Once you have the VpsAvailabilityFuture, you can obtain its result by polling or through a callback.

Poll the result

Use Future.getState() to obtain the state of the Future. There are three different states:

• PENDING: The operation is not yet complete, so no result is known.
• CANCELLED: The operation has been cancelled by Future.cancel(). Any registered callback will never be called.
• DONE: The operation is complete. Use VpsAvailabilityFuture.getResult() to obtain the result.

You may continue checking Future.getState() until the task is complete.

// Obtain a VpsAvailabilityFuture and store it somewhere.
VpsAvailabilityFuture future = session.checkVpsAvailabilityAsync(latitude, longitude, null);

// Poll VpsAvailabilityFuture later, for example, in a render loop.
if (future.getState() == FutureState.DONE) {
  switch (future.getResult()) {
    case AVAILABLE:
      // VPS is available at this location.
      break;
    case UNAVAILABLE:
      // VPS is unavailable at this location.
      break;
    case ERROR_NETWORK_CONNECTION:
      // The external service could not be reached due to a network connection error.
      break;

      // Handle other error states, e.g. ERROR_RESOURCE_EXHAUSTED, ERROR_INTERNAL, ...
  }
}

// Obtain a VpsAvailabilityFuture and store it somewhere.
val future = session.checkVpsAvailabilityAsync(latitude, longitude, null)

// Poll VpsAvailabilityFuture later, for example, in a render loop.
if (future.state == FutureState.DONE) {
  when (future.result) {
    VpsAvailability.AVAILABLE -> {
      // VPS is available at this location.
    }
    VpsAvailability.UNAVAILABLE -> {
      // VPS is unavailable at this location.
    }
    VpsAvailability.ERROR_NETWORK_CONNECTION -> {
      // The external service could not be reached due to a network connection error.
    }
    else -> {
      TODO("Handle other error states, e.g. ERROR_RESOURCE_EXHAUSTED, ERROR_INTERNAL, ...")
    }
  }
}

Obtain the result through a callback

You can also obtain the result of a Future through a callback. Use Session.checkVpsAvailabilityAsync() and supply a callback. This callback will be called on the Main thread soon after the Future has state DONE.

session.checkVpsAvailabilityAsync(
    latitude,
    longitude,
    result -> {
      // Callback is called on the Main thread.
      switch (result) {
          // Handle the VpsAvailability result as shown above.
          // For example, show UI that enables your AR view.
      }
    });

session.checkVpsAvailabilityAsync(latitude, longitude) { result ->
  // Callback is called on the Main thread.

  // Handle the VpsAvailability result as shown above.
  // For example, show UI that enables your AR view.
  TODO("Handle VpsAvailability " + result)
}

Cancel the Future

Use Future.cancel() to attempt to cancel the Future. Due to thread parallelism, it may be possible that your cancel attempt does not actually succeed. Future.cancel() returns true if this attempt was successful, and false otherwise.

Use the Geospatial API without VPS coverage

The Geospatial API can also be used in areas that do not have VPS coverage. In outdoor environments with few or no overhead obstructions, GPS may be sufficient to generate a pose with high accuracy.

What's next

• Obtain the device camera's Geospatial pose to determine the exact location of the user's device in the real world.