function calculateAndDisplayRoute(directionsService, directionsDisplay) {

  directionsService.route({
    origin: {lat: 37.77, lng: -122.447},
    destination: {lat: 37.768, lng: -122.511},

      travelMode: google.maps.TravelMode.WALKING
  }, function(response, status) {
    if (status == google.maps.DirectionsStatus.OK) {
      directionsDisplay.setDirections(response);
      console.log(response);
    } else {
      window.alert('Directions request failed due to ' + status);
    }
  });
}