+function calcTrackDuration() {
+ // Get the duration of the track in s.
+ var tDuration = 0;
+ if (gTrack.length > 1) {
+ for (var i = 1; i < gTrack.length; i++) {
+ if (!gTrack[i].beginSegment) {
+ tDuration += (gTrack[i].time - gTrack[i-1].time);
+ }
+ }
+ }
+ return Math.round(tDuration / 1000); // The timestamps are in ms but we return seconds.
+}
+
+function calcTrackLength() {
+ // Get the length of the track in km.
+ var tLength = 0;
+ if (gTrack.length > 1) {
+ for (var i = 1; i < gTrack.length; i++) {
+ if (!gTrack[i].beginSegment) {
+ tLength += getPointDistance(gTrack[i-1].coords, gTrack[i].coords);
+ }
+ }
+ }
+ return tLength;
+}
+
+function getPointDistance(aGPSPoint1, aGPSPoint2) {
+ // Get the distance in km between the two given GPS points.
+ // See http://stackoverflow.com/questions/365826/calculate-distance-between-2-gps-coordinates
+ // Earth is almost exactly a sphere and we calculate small distances on the surface, so we can do spherical great-circle math.
+ // Also see http://en.wikipedia.org/wiki/Great-circle_distance
+ var R = 6371; // km
+ var dLat = deg2rad(aGPSPoint2.latitude - aGPSPoint1.latitude);
+ var dLon = deg2rad(aGPSPoint2.longitude - aGPSPoint1.longitude);
+ var lat1 = deg2rad(aGPSPoint1.latitude);
+ var lat2 = deg2rad(aGPSPoint2.latitude);
+
+ var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
+ Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2);
+ var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
+ return R * c;
+}
+
+function deg2rad(aDegreeValue) {
+ // Convert an angle in degrees to radiants.
+ return aDegreeValue * (Math.PI / 180);
+}
+