Initial stab at per-payload onboard landing prediction markers.

Author: darksidelemm

js/tracker.js

@@ -919,6 +919,26 @@ function updateVehicleInfo(vcallsign, newPosition) {
     } else {
         vehicle.marker.setMode("parachute");
     }
+
+    // Update landing marker if data is available
+    if (newPosition.data.hasOwnProperty("pred_lat") && newPosition.data.hasOwnProperty("pred_lon")){
+        // Landing prediction data exists..
+        if (vehicle.landing_marker !== null){
+            // We already have a marker initialized.
+            if(newPosition.gps_alt > 350){
+                // Balloon is still in flight, so update the marker.
+                vehicle.landing_marker.setPosition(new google.maps.LatLng(newPosition.data.pred_lat, newPosition.data.pred_lon));
+                // Re-add to map if it's been removed previously.
+                if (vehicle.landing_marker.getMap() == null){
+                    vehicle.landing_marker.setMap(map);
+                }
+            }else{
+                // Balloon has landed, so hide the marker.
+                // Should we do this? Can we re-add it safely?
+                vehicle.landing_marker.setMap(null);
+            }
+        }
+    }
   }
 
   var image = vehicle.image_src;
@@ -1657,6 +1677,30 @@ function addPosition(position) {
                 this.setPosition(overlay.getProjection().fromDivPixelToLatLng(pos));
             };
 
+            // Add landing marker if the payload provides a predicted landing position.
+            if (position.data.hasOwnProperty('pred_lat') && position.data.hasOwnProperty('pred_lon')){
+                landing_image_src = host_url + markers_url + "balloon-xmark.png";
+                landing_image_src_size = new google.maps.Size(48,38);
+                landing_image_src_offset = new google.maps.Point(0,-38);
+
+                landing_marker = new google.maps.Marker({
+                    icon: {
+                        url: landing_image_src,
+                        size: landing_image_src_size,
+                        scaledSize: landing_image_src_size,
+                        anchor: new google.maps.Point(24,18)
+                    },
+                    zIndex: Z_CAR,
+                    position: new google.maps.LatLng(position.data.pred_lat, position.data.pred_lon),
+                    map: map,
+                    optimized: false,
+                    title: vcallsign + " Onboard Landing Prediction"
+                });
+                gmaps_elements.push(landing_marker);
+            } else {
+                landing_marker = null;
+            }
+
             horizon_circle = new google.maps.Circle({
                 map: map,
                 zIndex: Z_RANGE,
@@ -1790,6 +1834,7 @@ function addPosition(position) {
                             vehicle_type: vehicle_type,
                             marker: marker,
                             marker_shadow: marker_shadow,
+                            landing_marker: landing_marker,
                             image_src: image_src,
                             image_src_size: image_src_size,
                             image_src_offset: image_src_offset,