Nodejs Distance Calculate get_distance (lat1, lon1, lat2, lon2)

Method Source Code

function get_distance (lat1, lon1, lat2, lon2) {
   var R = 6371;//from  w w  w .j  av  a  2s.co  m
   var dLat = deg2rad(lat2-lat1);
   var dLon = deg2rad(lon2-lon1);
   var lat1 = deg2rad(lat1);
   var lat2 = deg2rad(lat2);

   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)); 
   var d = R * c;
   return Math.round(d * 1000);  // converting to meters
}

function deg2rad(deg) {
  return deg * (Math.PI/180)
}

function sort_by_distance (a, b) {
   if (a.distance < b.distance)
      return -1
   if (a.distance > b.distance)
      return 1
   return 0
}

// method for repeating same string num times
String.prototype.repeat = function( num )
{
    return new Array( num + 1 ).join( this );
}

Related

1. distance(p1, p2)

   function Point(x, y) {
       this.x = x;
       this.y = y;
   function randomPoint() {
       var randomx = randomNumber(WIDTH);
       var randomy = randomNumber(HEIGHT);
       var randomPoint = new Point(randomx, randomy);
       return randomPoint;
   ...
   

2. distance(x1, x2, y1, y2)

   Math.distance = function(x1, x2, y1, y2){
     var x = x2 - x1;
     var y = y2 - y1;
     return Math.sqrt(x * x + y * y);
   };
   

3. distanceBetweenTwoPoints(p1, p2)

   Util.distanceBetweenTwoPoints = function(p1, p2) {
     return Math.sqrt(Math.pow(p2.y - p1.y, 2) + Math.pow(p2.x - p1.x, 2)).toFixed(2);
   };
   

4. distanceOfTimeInWords(from, to)

   window.distanceOfTimeInWords = function (from, to) {
     var distance_in_milliseconds = to - from;
     var distance_in_minutes = Math.round(Math.abs(distance_in_milliseconds / 60000));
     var words = "";
     if (distance_in_minutes == 0) {
       words = "less than a minute";
     } else if (distance_in_minutes == 1) {
       words = "1 minute";
     } else if (distance_in_minutes < 45) {
   ...
   

5. getEditDistance(a, b)

   function getEditDistance(a, b){
     if(a.length == 0) return b.length;
     if(b.length == 0) return a.length;
     var matrix = [];
     var i;
     for(i = 0; i <= b.length; i++){
       matrix[i] = [i];
     var j;
   ...
   

6. haversineDistance(lat1, lng1, lat2, lng2)

   var haversineDistance(lat1, lng1, lat2, lng2) {
       var R = 6371; 
       var deltaLat = (lat2-lat1).inRadians();
       var deltaLng = (lng2-lng1).inRadians();
       var a = (Math.sin(deltaLat/2) * Math.sin(deltaLat/2)) + (Math.cos(lat1.inRadians()) * Math.cos(lat2.inRadians()) *
                      Math.sin(deltaLng/2) * Math.sin(deltaLng/2));
       var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
       return R * c; 
   

7. haversineDistance(lat1, lon1, lat2, lon2)

   function haversineDistance(lat1, lon1, lat2, lon2){
     var R = 6371; 
     var x1 = lat2-lat1;
     var dLat = x1.toRad();  
     var x2 = lon2-lon1;
     var dLon = x2.toRad();  
     var a = Math.sin(dLat/2) * Math.sin(dLat/2) + 
     Math.cos(lat1.toRad()) * Math.cos(lat2.toRad()) * 
     Math.sin(dLon/2) * Math.sin(dLon/2);  
   ...