Function: Distance between 2 points. Char unit is to know what metric to return. K returns kilometers. If the distance is less than 1km you have to return in meters. Returns strings (e.g.: 9 kms o 360 mts.)

Distance2points

private double distance(double startLat, double startLon, double endLat, double endLon, char unit){
  double theta = startLon - endLon;
  double dist = Math.sin(deg2rad(startLat)) * Math.sin(deg2rad(endLat)) + Math.cos(deg2rad(startLat)) * Math.cos(deg2rad(endLat)) * Math.cos(deg2rad(theta));
  dist = Math.acos(dist);
  dist = rad2deg(dist);
  dist = dist * 60 * 1.1515;
  if (unit == 'K') {
    dist = dist * 1.609344;
  } else if (unit == 'N') {
    dist = dist * 0.8684;
  }
  return (dist);
}