Feb
05
Calculate the distance between two sets of coordinates using JavaScript
Posted by | Posted in JavaScript Code | Posted on 05-02-2010
Tagged Under : gis, js, php, php2js
Here’s some code which allows you to calculate the distance in miles, kilometres or nautical miles between two sets of coordinates:
/* Function Name: distance()
Function Description: Calculates the distance between two sets of coordinates.
@Author: Adam Williams <adam.williams@awdigital.eu>
@License: Creative Commons Attribution-Share Alike 2.0 UK: England & Wales - http://creativecommons.org/licenses/by-sa/2.0/uk/
@Example: distance(53.61857936489517, -1.4501953125, 65.82078234733756, -172.265625, 'm');
*/
/* Dependant functions */
function deg2rad(angle) {
return (angle * Math.PI / 180);
}
function rad2deg (angle) {
return (angle / Math.PI) * 180;
}
/* Main function */
function distance(lat1, lon1, lat2, lon2, unit) {
var theta, dist, miles;
theta = lon1 - lon2;
dist = Math.sin(deg2rad(lat1)) * Math.sin(deg2rad(lat2)) + Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * Math.cos(deg2rad(theta));
dist = Math.acos(dist);
dist = rad2deg(dist);
miles = dist * 60 * 1.1515;
unit = unit.toUpperCase();
if (unit === "K") {
return (miles * 1.609344);
} else if (unit === "N") {
return (miles * 0.8684);
} else {
return miles;
}
}
You can download the code if you don’t want to copy and paste: distance.js
Any feedback welcomed.
Cheers! 