traque/traque-back/map_utils.js

export function getDistanceFromLatLon({lat: lat1, lng: lon1}, {lat: lat2, lng: 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 * 1000;
}

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

export function isInCircle(position, center, radius) {
    return getDistanceFromLatLon(position, center) < radius;
}