utils changes

lib/geomUtils.js

@@ -11,6 +11,13 @@ if (!Number.prototype.toRad) {
 
 }
 
+if (!Number.prototype.toDeg) {
+	Number.prototype.toDeg = function() {
+		return this * 180/ Math.PI;
+	};
+
+}
+
 var greatCircleRadius = {
 	miles: 3956,
 	km: 6367
@@ -22,9 +29,10 @@ var greatCircleRadius = {
  * @param {number} lon1 The longtitude of the first point.
  * @param {number} lat2 The latitude of the first point.
  * @param {number} lon2 The longtitude of the first point.
- * @returns {number} The distance in miles between the two points.
+ * @param {boolean} [inMiles=False] Specifies if result should be in miles.
+ * @returns {number} The distance in kilometers (or miles) between the two points.
 **/
-exports.calculateDistance = function(lat1, lon1, lat2, lon2) {
+exports.calculateDistance = function(lat1, lon1, lat2, lon2, inMiles) {
 	var dLat = (lat2 - lat1).toRad(),
 		dLon = (lon2 - lon1).toRad();
 
@@ -34,7 +42,7 @@ exports.calculateDistance = function(lat1, lon1, lat2, lon2) {
 	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 greatCircleRadius.km * c;
+	return (inMiles ? greatCircleRadius.miles : greatCircleRadius.km) * c;
 };
 
 /**
@@ -43,17 +51,18 @@ exports.calculateDistance = function(lat1, lon1, lat2, lon2) {
  * @param {number} lon1 The longtitude of the first point.
  * @param {number} lat2 The latitude of the first point.
  * @param {number} lon2 The longtitude of the first point.
+ * @returns {Array<number>} An array of latitude and longtitude values of the midpoint.
  */
 exports.calculateMidpoint = function(lat1, lon1, lat2, lon2) {
-	var dLat = (lat2 - lat1).toRad(),
-		dLon = (lon2 - lon1).toRad();
-
-	lat1 = lat1.toRad();
+    var dLon = (lon2 - lon1).toRad();
+
+    lat1 = lat1.toRad();
 	lat2 = lat2.toRad();
-
-	var Bx = Math.cos(lat2) * Math.cos(dLon);
+  
+    var Bx = Math.cos(lat2) * Math.cos(dLon);
 	var By = Math.cos(lat2) * Math.sin(dLon);
-	var lat3 = Math.atan2(Math.sin(lat1) + Math.sin(lat2),
-		Math.sqrt((Math.cos(lat1) + Bx) * (Math.cos(lat1) + Bx) + By * By));
-	var lon3 = lon1 + Math.atan2(By, Math.cos(lat1) + Bx);
+	var lat3 = (Math.atan2(Math.sin(lat1) + Math.sin(lat2),
+		Math.sqrt((Math.cos(lat1) + Bx) * (Math.cos(lat1) + Bx) + By * By))).toDeg();
+	var lon3 = lon1 + Math.atan2(By, Math.cos(lat1) + Bx).toDeg();
+	return [lat3,lon3];
 };

tests/utils-tests.js

@@ -11,13 +11,19 @@ module.exports = {
     },
 
     "Should calculate the distance between two points": function(test) {
-        var distance = geomUtils.calculateDistance(4.367, 5.6745, -40.4556, 39.34345);
-        test.equal(distance, 6045.97811789512);
+        var distanceInKm = geomUtils.calculateDistance(4.367, 5.6745, -40.4556, 39.34345);
+        var distanceInMiles = geomUtils.calculateDistance(4.367, 5.6745, -40.4556, 39.34345, true);
+
+        test.equal(distanceInKm, 6045.97811789512);
+        test.equal(distanceInMiles, distanceInKm/1.609453993933266 ); 
         test.done();
     },
 
     "Should calculate the midpoint between two points" : function(test) {
-        geomUtils.calculateMidpoint(4.367, 5.6745, -40.4556, 39.34345);
+        var midpoint = geomUtils.calculateMidpoint(4.367, 5.6745, -40.4556, 39.34345);
+
+        test.deepEqual(midpoint, [ -18.7821348599706, 20.181135926320035] );
         test.done();
     }
 };
+