JavaScript API上的标记图标

Question

我正在尝试使用下面的Google API示例，为标记添加自定义图标。我不确定在示例中将其添加到何处，因为它会循环并为多个位置创建路线。我只想将默认标记换成其他图标。有人可以建议在哪里添加代码以实际替换图标吗？

具体地，使用下面的代码（来自Google示例）：

 <script>
      function initMap() {
        var directionsService = new google.maps.DirectionsService;
        //var directionsDisplay = new google.maps.DirectionsRenderer;

        var image = 'https://mysite/ubt.png';

        var directionsDisplay = new google.maps.DirectionsRenderer({
    draggable: true,
    map: map,
    panel: document.getElementById('right-panel')
          });

        var map = new google.maps.Map(document.getElementById('map'), {
          zoom: 6,
          center: {lat: 42.880230, lng: -78.878738}
        });
        directionsDisplay.setMap(map);

        document.getElementById('submit').addEventListener('click', function() {
          calculateAndDisplayRoute(directionsService, directionsDisplay);
        });
      }

      function calculateAndDisplayRoute(directionsService, directionsDisplay) {


        var waypts = [];
        var checkboxArray = document.getElementById('waypoints');
        for (var i = 0; i < checkboxArray.length; i++) {
          if (checkboxArray.options[i].selected) {
            waypts.push({
              location: checkboxArray[i].value,
              stopover: true
            });
          }
        }

        directionsService.route({
          origin: document.getElementById('start').value,
          destination: document.getElementById('end').value,
          waypoints: waypts,
          optimizeWaypoints: true,
          travelMode: 'DRIVING'
        }, function(response, status) {
          if (status === 'OK') {
            directionsDisplay.setDirections(response);
            var route = response.routes[0];
            var summaryPanel = document.getElementById('directions-panel');
            summaryPanel.innerHTML = '';
            // For each route, display summary information.
            for (var i = 0; i < route.legs.length; i++) {
              var routeSegment = i + 1;
              summaryPanel.innerHTML += '<b>Route Segment: ' + routeSegment +
                  '</b><br>';
              summaryPanel.innerHTML += route.legs[i].start_address + ' to ';
              summaryPanel.innerHTML += route.legs[i].end_address + '<br>';
              summaryPanel.innerHTML += route.legs[i].distance.text + '<br><br>';
            }
          } else {
            window.alert('Directions request failed due to ' + status);
          }
        });
      }
    </script>

示例：

https://developers.google.com/maps/documentation/javascript/examples/directions-waypoints