[javascript] Function to calculate distance between two coordinates

I'm currently using the function below and it doesn't work properly. According to Google Maps, the distance between these coordinates (from 59.3293371,13.4877472 to 59.3225525,13.4619422) are 2.2 kilometres while the function returns 1.6 kilometres. How can I make this function return the correct distance?

function getDistanceFromLatLonInKm(lat1, lon1, lat2, lon2) {
  var R = 6371; // Radius of the earth in km
  var dLat = deg2rad(lat2-lat1);  // deg2rad below
  var dLon = deg2rad(lon2-lon1); 
  var a = 
    Math.sin(dLat/2) * Math.sin(dLat/2) +
    Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * 
    Math.sin(dLon/2) * Math.sin(dLon/2)
    ; 
  var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
  var d = R * c; // Distance in km
  return d;
}

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

jsFiddle: http://jsfiddle.net/edgren/gAHJB/

I have written a similar equation before - tested it and also got 1.6 km.

Your google maps was showing the DRIVING distance.

Your function is calculating as the crow flies (straight line distance).

alert(calcCrow(59.3293371,13.4877472,59.3225525,13.4619422).toFixed(1));



    //This function takes in latitude and longitude of two location and returns the distance between them as the crow flies (in km)
    function calcCrow(lat1, lon1, lat2, lon2) 
    {
      var R = 6371; // km
      var dLat = toRad(lat2-lat1);
      var dLon = toRad(lon2-lon1);
      var lat1 = toRad(lat1);
      var lat2 = toRad(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 d;
    }

    // Converts numeric degrees to radians
    function toRad(Value) 
    {
        return Value * Math.PI / 180;
    }

Adding this for Node.JS users. You can use the haversine-distance module to do this so you won't need to handle the calculations on your own. See the npm page for more information.

To install:

npm install --save haversine-distance

You can use the module as follows:

var haversine = require("haversine-distance");

//First point in your haversine calculation
var point1 = { lat: 6.1754, lng: 106.8272 }

//Second point in your haversine calculation
var point2 = { lat: 6.1352, lng: 106.8133 }

var haversine_m = haversine(point1, point2); //Results in meters (default)
var haversine_km = haversine_m /1000; //Results in kilometers

console.log("distance (in meters): " + haversine_m + "m");
console.log("distance (in kilometers): " + haversine_km + "km");

Calculate the Distance between Two Points in javascript

function distance(lat1, lon1, lat2, lon2, unit) {
        var radlat1 = Math.PI * lat1/180
        var radlat2 = Math.PI * lat2/180
        var theta = lon1-lon2
        var radtheta = Math.PI * theta/180
        var dist = Math.sin(radlat1) * Math.sin(radlat2) + Math.cos(radlat1) * Math.cos(radlat2) * Math.cos(radtheta);
        dist = Math.acos(dist)
        dist = dist * 180/Math.PI
        dist = dist * 60 * 1.1515
        if (unit=="K") { dist = dist * 1.609344 }
        if (unit=="N") { dist = dist * 0.8684 }
        return dist
}

For more details refer this: Reference Link

Derek's solution worked fine for me, and I've just simply converted it to PHP, hope it helps somebody out there !

function calcCrow($lat1, $lon1, $lat2, $lon2){
        $R = 6371; // km
        $dLat = toRad($lat2-$lat1);
        $dLon = toRad($lon2-$lon1);
        $lat1 = toRad($lat1);
        $lat2 = toRad($lat2);

        $a = sin($dLat/2) * sin($dLat/2) +sin($dLon/2) * sin($dLon/2) * cos($lat1) * cos($lat2); 
        $c = 2 * atan2(sqrt($a), sqrt(1-$a)); 
        $d = $R * $c;
        return $d;
}

// Converts numeric degrees to radians
function toRad($Value) 
{
    return $Value * pi() / 180;
}

Using Haversine formula, source of the code:

//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
//:::                                                                         :::
//:::  This routine calculates the distance between two points (given the     :::
//:::  latitude/longitude of those points). It is being used to calculate     :::
//:::  the distance between two locations using GeoDataSource (TM) prodducts  :::
//:::                                                                         :::
//:::  Definitions:                                                           :::
//:::    South latitudes are negative, east longitudes are positive           :::
//:::                                                                         :::
//:::  Passed to function:                                                    :::
//:::    lat1, lon1 = Latitude and Longitude of point 1 (in decimal degrees)  :::
//:::    lat2, lon2 = Latitude and Longitude of point 2 (in decimal degrees)  :::
//:::    unit = the unit you desire for results                               :::
//:::           where: 'M' is statute miles (default)                         :::
//:::                  'K' is kilometers                                      :::
//:::                  'N' is nautical miles                                  :::
//:::                                                                         :::
//:::  Worldwide cities and other features databases with latitude longitude  :::
//:::  are available at https://www.geodatasource.com                         :::
//:::                                                                         :::
//:::  For enquiries, please contact [email protected]                  :::
//:::                                                                         :::
//:::  Official Web site: https://www.geodatasource.com                       :::
//:::                                                                         :::
//:::               GeoDataSource.com (C) All Rights Reserved 2018            :::
//:::                                                                         :::
//:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

function distance(lat1, lon1, lat2, lon2, unit) {
    if ((lat1 == lat2) && (lon1 == lon2)) {
        return 0;
    }
    else {
        var radlat1 = Math.PI * lat1/180;
        var radlat2 = Math.PI * lat2/180;
        var theta = lon1-lon2;
        var radtheta = Math.PI * theta/180;
        var dist = Math.sin(radlat1) * Math.sin(radlat2) + Math.cos(radlat1) * Math.cos(radlat2) * Math.cos(radtheta);
        if (dist > 1) {
            dist = 1;
        }
        dist = Math.acos(dist);
        dist = dist * 180/Math.PI;
        dist = dist * 60 * 1.1515;
        if (unit=="K") { dist = dist * 1.609344 }
        if (unit=="N") { dist = dist * 0.8684 }
        return dist;
    }
}

The sample code is licensed under LGPLv3.

Great-circle distance - From chord length

Here's an elegant solution applying the strategy design pattern; I hope it's readable enough.

TwoPointsDistanceCalculatorStrategy.js:

module.exports = () =>

class TwoPointsDistanceCalculatorStrategy {

    constructor() {}

    calculateDistance({ point1Coordinates, point2Coordinates }) {}
};

GreatCircleTwoPointsDistanceCalculatorStrategy.js:

module.exports = ({ TwoPointsDistanceCalculatorStrategy }) =>

class GreatCircleTwoPointsDistanceCalculatorStrategy extends TwoPointsDistanceCalculatorStrategy {

    constructor() {
        super();
    }

    /**
     * Following the algorithm documented here: 
     * https://en.wikipedia.org/wiki/Great-circle_distance#Computational_formulas
     * 
     * @param {object} inputs
     * @param {array} inputs.point1Coordinates
     * @param {array} inputs.point2Coordinates
     * 
     * @returns {decimal} distance in kelometers
     */
    calculateDistance({ point1Coordinates, point2Coordinates }) {

        const convertDegreesToRadians = require('../convert-degrees-to-radians');
        const EARTH_RADIUS = 6371;   // in kelometers

        const [lat1 = 0, lon1 = 0] = point1Coordinates;
        const [lat2 = 0, lon2 = 0] = point2Coordinates;

        const radianLat1 = convertDegreesToRadians({ degrees: lat1 });
        const radianLon1 = convertDegreesToRadians({ degrees: lon1 });
        const radianLat2 = convertDegreesToRadians({ degrees: lat2 });
        const radianLon2 = convertDegreesToRadians({ degrees: lon2 });

        const centralAngle = _computeCentralAngle({ 
            lat1: radianLat1, lon1: radianLon1, 
            lat2: radianLat2, lon2: radianLon2, 
        });

        const distance = EARTH_RADIUS * centralAngle;

        return distance;
    }
};


/**
 * 
 * @param {object} inputs
 * @param {decimal} inputs.lat1
 * @param {decimal} inputs.lon1
 * @param {decimal} inputs.lat2
 * @param {decimal} inputs.lon2
 * 
 * @returns {decimal} centralAngle
 */
function _computeCentralAngle({ lat1, lon1, lat2, lon2 }) {

    const chordLength = _computeChordLength({ lat1, lon1, lat2, lon2 });
    const centralAngle = 2 * Math.asin(chordLength / 2);

    return centralAngle;
}


/**
 * 
 * @param {object} inputs
 * @param {decimal} inputs.lat1
 * @param {decimal} inputs.lon1
 * @param {decimal} inputs.lat2
 * @param {decimal} inputs.lon2
 * 
 * @returns {decimal} chordLength
 */
function _computeChordLength({ lat1, lon1, lat2, lon2 }) {

    const { sin, cos, pow, sqrt } = Math;

    const ?X = cos(lat2) * cos(lon2) - cos(lat1) * cos(lon1);
    const ?Y = cos(lat2) * sin(lon2) - cos(lat1) * sin(lon1);
    const ?Z = sin(lat2) - sin(lat1);

    const ?XSquare = pow(?X, 2);
    const ?YSquare = pow(?Y, 2);
    const ?ZSquare = pow(?Z, 2);

    const chordLength = sqrt(?XSquare + ?YSquare + ?ZSquare);

    return chordLength;
}

convert-degrees-to-radians.js:

module.exports = function convertDegreesToRadians({ degrees }) {

    return degrees * Math.PI / 180;
};

This's following the Great-circle distance - From chord length, documented here.

I implemeneted this algorithm in typescript and ES6

export type Coordinate = {
  lat: number;
  lon: number;
};

get the distance between two points:

function getDistanceBetweenTwoPoints(cord1: Coordinate, cord2: Coordinate) {
  if (cord1.lat == cord2.lat && cord1.lon == cord2.lon) {
    return 0;
  }

  const radlat1 = (Math.PI * cord1.lat) / 180;
  const radlat2 = (Math.PI * cord2.lat) / 180;

  const theta = cord1.lon - cord2.lon;
  const radtheta = (Math.PI * theta) / 180;

  let dist =
    Math.sin(radlat1) * Math.sin(radlat2) +
    Math.cos(radlat1) * Math.cos(radlat2) * Math.cos(radtheta);

  if (dist > 1) {
    dist = 1;
  }

  dist = Math.acos(dist);
  dist = (dist * 180) / Math.PI;
  dist = dist * 60 * 1.1515;
  dist = dist * 1.609344; //convert miles to km
  
  return dist;
}

get the distance between an array of coordinates

export function getTotalDistance(coordinates: Coordinate[]) {
  coordinates = coordinates.filter((cord) => {
    if (cord.lat && cord.lon) {
      return true;
    }
  });
  
  let totalDistance = 0;

  if (!coordinates) {
    return 0;
  }

  if (coordinates.length < 2) {
    return 0;
  }

  for (let i = 0; i < coordinates.length - 2; i++) {
    if (
      !coordinates[i].lon ||
      !coordinates[i].lat ||
      !coordinates[i + 1].lon ||
      !coordinates[i + 1].lat
    ) {
      totalDistance = totalDistance;
    }
    totalDistance =
      totalDistance +
      getDistanceBetweenTwoPoints(coordinates[i], coordinates[i + 1]);
  }

  return totalDistance.toFixed(2);
}

As said before, your function is calculating a straight line distance to the destination point. If you want the driving distance/route, you can use Google Maps Distance Matrix Service:

getDrivingDistanceBetweenTwoLatLong(origin, destination) {

 return new Observable(subscriber => {
  let service = new google.maps.DistanceMatrixService();
  service.getDistanceMatrix(
    {
      origins: [new google.maps.LatLng(origin.lat, origin.long)],
      destinations: [new google.maps.LatLng(destination.lat, destination.long)],
      travelMode: 'DRIVING'
    }, (response, status) => {
      if (status !== google.maps.DistanceMatrixStatus.OK) {
        console.log('Error:', status);
        subscriber.error({error: status, status: status});
      } else {
        console.log(response);
        try {
          let valueInMeters = response.rows[0].elements[0].distance.value;
          let valueInKms = valueInMeters / 1000;
          subscriber.next(valueInKms);
          subscriber.complete();
        }
       catch(error) {
        subscriber.error({error: error, status: status});
       }
      }
    });
});
}

Try this. It is in VB.net and you need to convert it to Javascript. This function accepts parameters in decimal minutes.

    Private Function calculateDistance(ByVal long1 As String, ByVal lat1 As String, ByVal long2 As String, ByVal lat2 As String) As Double
    long1 = Double.Parse(long1)
    lat1 = Double.Parse(lat1)
    long2 = Double.Parse(long2)
    lat2 = Double.Parse(lat2)

    'conversion to radian
    lat1 = (lat1 * 2.0 * Math.PI) / 60.0 / 360.0
    long1 = (long1 * 2.0 * Math.PI) / 60.0 / 360.0
    lat2 = (lat2 * 2.0 * Math.PI) / 60.0 / 360.0
    long2 = (long2 * 2.0 * Math.PI) / 60.0 / 360.0

    ' use to different earth axis length
    Dim a As Double = 6378137.0        ' Earth Major Axis (WGS84)
    Dim b As Double = 6356752.3142     ' Minor Axis
    Dim f As Double = (a - b) / a        ' "Flattening"
    Dim e As Double = 2.0 * f - f * f      ' "Eccentricity"

    Dim beta As Double = (a / Math.Sqrt(1.0 - e * Math.Sin(lat1) * Math.Sin(lat1)))
    Dim cos As Double = Math.Cos(lat1)
    Dim x As Double = beta * cos * Math.Cos(long1)
    Dim y As Double = beta * cos * Math.Sin(long1)
    Dim z As Double = beta * (1 - e) * Math.Sin(lat1)

    beta = (a / Math.Sqrt(1.0 - e * Math.Sin(lat2) * Math.Sin(lat2)))
    cos = Math.Cos(lat2)
    x -= (beta * cos * Math.Cos(long2))
    y -= (beta * cos * Math.Sin(long2))
    z -= (beta * (1 - e) * Math.Sin(lat2))

    Return Math.Sqrt((x * x) + (y * y) + (z * z))
End Function

Edit The converted function in javascript

function calculateDistance(lat1, long1, lat2, long2)
  {    

      //radians
      lat1 = (lat1 * 2.0 * Math.PI) / 60.0 / 360.0;      
      long1 = (long1 * 2.0 * Math.PI) / 60.0 / 360.0;    
      lat2 = (lat2 * 2.0 * Math.PI) / 60.0 / 360.0;   
      long2 = (long2 * 2.0 * Math.PI) / 60.0 / 360.0;       


      // use to different earth axis length    
      var a = 6378137.0;        // Earth Major Axis (WGS84)    
      var b = 6356752.3142;     // Minor Axis    
      var f = (a-b) / a;        // "Flattening"    
      var e = 2.0*f - f*f;      // "Eccentricity"      

      var beta = (a / Math.sqrt( 1.0 - e * Math.sin( lat1 ) * Math.sin( lat1 )));    
      var cos = Math.cos( lat1 );    
      var x = beta * cos * Math.cos( long1 );    
      var y = beta * cos * Math.sin( long1 );    
      var z = beta * ( 1 - e ) * Math.sin( lat1 );      

      beta = ( a / Math.sqrt( 1.0 -  e * Math.sin( lat2 ) * Math.sin( lat2 )));    
      cos = Math.cos( lat2 );   
      x -= (beta * cos * Math.cos( long2 ));    
      y -= (beta * cos * Math.sin( long2 ));    
      z -= (beta * (1 - e) * Math.sin( lat2 ));       

      return (Math.sqrt( (x*x) + (y*y) + (z*z) )/1000);  
    }

I try to make the code a little bit understandable by naming the variables, I hope this can help

function getDistanceFromLatLonInKm(point1, point2) {

  const [lat1, lon1] = point1;
  const [lat2, lon2] = point2;
  const earthRadius = 6371;
  const dLat = convertDegToRad(lat2 - lat1);
  const dLon = convertDegToRad(lon2 - lon1);
  const squarehalfChordLength =
    Math.sin(dLat / 2) * Math.sin(dLat / 2) +
    Math.cos(convertDegToRad(lat1)) * Math.cos(convertDegToRad(lat2)) *
    Math.sin(dLon / 2) * Math.sin(dLon / 2);

  const angularDistance = 2 * Math.atan2(Math.sqrt(squarehalfChordLength), Math.sqrt(1 - squarehalfChordLength));
  const distance = earthRadius * angularDistance;
  return distance;

}

Visit this address. https://www.movable-type.co.uk/scripts/latlong.html You can use this code:

JavaScript:     

const R = 6371e3; // metres
const f1 = lat1 * Math.PI/180; // f, ? in radians
const f2 = lat2 * Math.PI/180;
const ?f = (lat2-lat1) * Math.PI/180;
const ?? = (lon2-lon1) * Math.PI/180;

const a = Math.sin(?f/2) * Math.sin(?f/2) +
          Math.cos(f1) * Math.cos(f2) *
          Math.sin(??/2) * Math.sin(??/2);
const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

const d = R * c; // in metres

I have written the function to find distance between two coordinates. It will return distance in meter.

 function findDistance() {
   var R = 6371e3; // R is earth’s radius
   var lat1 = 23.18489670753479; // starting point lat
   var lat2 = 32.726601;         // ending point lat
   var lon1 = 72.62524545192719; // starting point lon
   var lon2 = 74.857025;         // ending point lon
   var lat1radians = toRadians(lat1);
   var lat2radians = toRadians(lat2);

   var latRadians = toRadians(lat2-lat1);
   var lonRadians = toRadians(lon2-lon1);

   var a = Math.sin(latRadians/2) * Math.sin(latRadians/2) +
        Math.cos(lat1radians) * Math.cos(lat2radians) *
        Math.sin(lonRadians/2) * Math.sin(lonRadians/2);
   var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));

   var d = R * c;

   console.log(d)
}

function toRadians(val){
    var PI = 3.1415926535;
    return val / 180.0 * PI;
}