Finally I can calculate distance from ISS.

1 files changed, 53 insertions, 18 deletions

diff --git a/iss_get_data.js b/iss_get_data.js
index 9ba7069..0db03c8 100755
--- a/iss_get_data.js
+++ b/iss_get_data.js
@@ -70,7 +70,6 @@ const ISS_Above = new GObject.Class({
       'org.freedesktop.GeoClue2', '/org/freedesktop/GeoClue2/Manager');
 
     [this.clientAddr] = this.managerProxy.GetClientSync();
-    print('this.clientAddr = ' + this.clientAddr);
 
     this.current_location = {};
     this.iss_coords = null;
@@ -96,7 +95,7 @@ const ISS_Above = new GObject.Class({
     let iss_api = Gio.file_new_for_uri(API_URL);
     iss_api.load_contents_async(null, function(iss_api, result) {
       self.iss_coords = JSON.parse(iss_api.load_contents_finish(result)[1]);
-      print(self.iss_coords.toSource());
+      // print(self.iss_coords.toSource());
       self.emit('processed_data');
     });
   },
@@ -105,31 +104,67 @@ const ISS_Above = new GObject.Class({
     let geoclueLocation = new LocationProxy(Gio.DBus.system,
                                             "org.freedesktop.GeoClue2",
                                             newPath);
-    print('location:');
-    print('\tlatitude = '    + geoclueLocation.latitude);
-    print('\tlongitude = '   + geoclueLocation.longitude);
-    print('\taccuracy = '    + geoclueLocation.accuracy);
-    print('\tdescription = ' + geoclueLocation.description);
 
-    // this.current_location.latitude = geoclueLocation.latitude;
-    // this.current_location.longitude = geoclueLocation.longitude;
-    // this.current_location.accuracy = geoclueLocation.accuracy;
-    // this.current_location.description = geoclueLocation.description;
+    this.current_location.Latitude = geoclueLocation.Latitude;
+    this.current_location.Longitude = geoclueLocation.Longitude;
+    this.current_location.Accuracy = geoclueLocation.Accuracy;
+    this.current_location.Description = geoclueLocation.Description;
 
     this.emit('processed_data');
   },
 
+  /** 
+   * Calculate distance in km of two geographical points
+   *
+   * @param lat1  Number latitude of the first point
+   * @param long1 Number longitude of the first point
+   * @param lat2  Number latitude of the second point
+   * @param long2 Number longitude of the second point
+   * @return Number distance in km
+   *
+   * Described on https://en.wikipedia.org/wiki/Haversine_formula
+   */
+  get_distance: function(lat1, long1, lat2, long2) {
+    // Mean radius of the Earth in km
+    const EARTH_R = 6371;
+    const PI_180 = Math.PI / 180;
+
+    function haversin(fi) {
+      return (1 - Math.cos(fi)) / 2;
+    }
+
+    lat1 = lat1 * PI_180;
+    long1 = long1 * PI_180;
+    lat2 = lat2 * PI_180;
+    long2 = long2 * PI_180;
+
+    let dist = 2 * EARTH_R *
+      Math.asin(Math.sqrt(haversin(lat2 - lat1) +
+        Math.cos(lat1) * Math.cos(lat2) * haversin(long2 - long1)));
+
+    let test_haversin = haversin(dist / EARTH_R);
+    if (test_haversin < 1) {
+      return dist.toFixed(3);
+    }
+    else {
+      throw new Error('haversine(d/r) cannot be over 1, but it is ' +
+          test_haversin);
+    }
+  },
+
   processResult: function() {
     this.task_queue--;
-    print('this.task_queue = ' + this.task_queue);
 
     if (this.task_queue === 0) {
-      print('location:');
-      print('\tlatitude = ' + this.current_location.latitude);
-      print('\tlongitude = ' + this.current_location.longitude);
-      print('\taccuracy = ' + this.current_location.accuracy);
-      print('\tdescription = ' + this.current_location.description);
-      print('\n\niss coordinates: ' + this.iss_coords.toSource());
+      // print('our location: ' + this.current_location.toSource());
+      // print('iss coordinates: ' + this.iss_coords.toSource());
+
+      let dist = this.get_distance(this.current_location.Latitude,
+          this.current_location.Longitude,
+          this.iss_coords.iss_position.latitude,
+          this.iss_coords.iss_position.longitude)
+
+      print('ISS is ' + dist + ' km away.');
 
       Mainloop.quit();
     }