Initial commit.

server/lib/maps.js

@@ -0,0 +1,94 @@
+/*
+ * Latitude/longitude spherical geodesy formulae & scripts (c) Chris Veness 2002-2012
+ * From: http://www.movable-type.co.uk/scripts/latlong.html
+ */
+
+if (typeof Number.prototype.toRad == 'undefined') {
+  Number.prototype.toRad = function() {
+    return this * Math.PI / 180;
+  };
+}
+
+if (typeof Number.prototype.toDeg == 'undefined') {
+  Number.prototype.toDeg = function() {
+    return this * 180 / Math.PI;
+  };
+}
+
+function computeDistance(from, to) {
+  // Equirectangular approximation, should be enough as distances are small
+  var R = 6371000; // km
+  var x = (to[1].toRad() - from[1].toRad()) * Math.cos((from[0].toRad() + to[0].toRad()) / 2);
+  var y = (from[0].toRad() - to[0].toRad());
+  return Math.sqrt(x * x + y * y) * R;
+}
+
+function computeInitialBearing(from, to) {
+  var dLat = (to[0] - from[0]).toRad();
+  var dLon = (to[1] - from[1]).toRad();
+  var lat1 = from[0].toRad();
+  var lat2 = to[0].toRad();
+
+  var y = Math.sin(dLon) * Math.cos(lat2);
+  var x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1) * Math.cos(lat2) * Math.cos(dLon);
+  return (Math.atan2(y, x).toDeg() + 360) % 360;
+}
+
+function computeFinalBearing(from, to) {
+  return (computeInitialBearing(to, from) + 180) % 360;
+}
+
+// Rest are copied from: https://github.com/moshen/node-googlemaps/blob/master/lib/googlemaps.js
+function createEncodedPolyline(points) {
+  // Dear maintainer:
+  //
+  // Once you are done trying to 'optimize' this routine,
+  // and have realized what a terrible mistake that was,
+  // please increment the following counter as a warning
+  // to the next guy:
+  //
+  // total_hours_wasted_here = 11
+  //
+  var i, dlat, dlng;
+  var plat = 0;
+  var plng = 0;
+  var encoded_points = "";
+  if(typeof points === 'string'){
+    points = points.split('|');
+  }
+
+  for(i = 0; i < points.length; i++) {
+    var point = points[i];//.split(',');
+    var lat = point[0];
+    var lng = point[1];
+    var late5 = Math.round(lat * 1e5);
+    var lnge5 = Math.round(lng * 1e5);
+    dlat = late5 - plat;
+    dlng = lnge5 - plng;
+    plat = late5;
+    plng = lnge5;
+    encoded_points += encodeSignedNumber(dlat) + encodeSignedNumber(dlng);
+  }
+  return encoded_points;
+}
+
+function encodeNumber(num) {
+  var encodeString = "";
+  var nextValue, finalValue;
+  while (num >= 0x20) {
+    nextValue = (0x20 | (num & 0x1f)) + 63;
+    encodeString += (String.fromCharCode(nextValue));
+    num >>= 5;
+  }
+  finalValue = num + 63;
+  encodeString += (String.fromCharCode(finalValue));
+  return encodeString;
+}
+
+function encodeSignedNumber(num) {
+  var sgn_num = num << 1;
+  if (num < 0) {
+    sgn_num = ~(sgn_num);
+  }
+  return(encodeNumber(sgn_num));
+}