Lalit Kumar - 4 months ago 18x
Node.js Question

# How we calculate distance between two co-ordinate. ArangoDB

I have a Users table that contains latitude and longitude attribute for every user. So I need to calculate the distance between two users in AQL Query.

I have done the same in Orientdb with the below query.

``````var laltitude = CURRENT_USER_laltitude;
var longitude = CURRENT_USER_longitude;
var query = "select distance(latitude, longitude,"+laltitude+","+longitude+") as distance from users";
``````

First, create a js file distance.js (or whatever you want to name it) and put below code as below.

``````/* distance.js */
'use strict';

function gdistance(latitude1, longitude1, latitude2, longitude2, radius) {
if (!latitude1 || !longitude1 || !latitude2 || !longitude2) {
return null;
};

var lat1 = Number(latitude1), lon1 = Number(longitude1);
var lat2 = Number(latitude2), lon2 = Number(longitude2);

var R = radius;
var φ1 = (lat1 * Math.PI / 180), λ1 = (lon1 * Math.PI / 180);
var φ2 = (lat2 * Math.PI / 180), λ2 = (lon2 * Math.PI / 180);
var Δφ = φ2 - φ1;
var Δλ = λ2 - λ1;

var a = Math.sin(Δφ/2) * Math.sin(Δφ/2)
+ Math.cos(φ1) * Math.cos(φ2)
* Math.sin(Δλ/2) * Math.sin(Δλ/2);
var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
var d = R * c;     // Meters
var d2 = d / 1000; // Meters to KM
return d2;
}

module.exports = gdistance;
``````

Now open Arango Console with `arangosh`. This will open with `_system` database by default. So if you have other than this database like me then use `db._useDatabase("myDatabase")` command to change database.

Now write below commands to add custom to your desired database.

``````db._useDatabase("myDatabase");
var aqlfunctions = require("org/arangodb/aql/functions");
var f = require("/path/to/file/distance.js");
aqlfunctions.register("geo::gdistance", f, true)
``````

Now use in your AQL queries as below.

``````LET distance = geo::gdistance(attrbute_name.latitude, attrbute_name.longitude, @your_latitude, @your_longitude)
``````

For more references with here.