Calculate Distance

5 parameters

5 of 6

function calculateDistance(lat1, lon1, lat2, lon2, unit)

Calculates the distance between two geographic coordinates using the Haversine formula

Name:calculateDistance

Parameters

Name↑	Type	Required	Description
lat1	number	Required	Latitude of the first point
lat2	number	Required	Latitude of the second point
lon1	number	Required	Longitude of the first point
lon2	number	Required	Longitude of the second point
unit	string	Optional	Unit of measurement (km or miles)

Function Implementation

function calculateDistance(lat1, lon1, lat2, lon2, unit = 'km') {
  const R = unit === 'km' ? 6371 : 3959; // Earth's radius
  const dLat = toRad(lat2 - lat1);
  const dLon = toRad(lon2 - lon1);
  const a = 
    Math.sin(dLat/2) * Math.sin(dLat/2) +
    Math.cos(toRad(lat1)) * Math.cos(toRad(lat2)) * 
    Math.sin(dLon/2) * Math.sin(dLon/2);
  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
  return R * c;
  
  function toRad(deg) {
    return deg * (Math.PI/180);
  }
}