緯度経度から二点間距離の計算をざっくり

gistfile1.txt

  private double deg2rad(double deg) {
    return (deg * Math.PI / 180.0);
  }
  private double rad2deg(double rad) {
    return (rad * 180.0 / Math.PI);
  }
  
  @Kroll.method
  public Double calcDistance(double lat1, double lon1, double lat2, double lon2, String unit){
    double theta = lon1 - lon2;
    double 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);
    dist = dist * 60 * 1.1515;//miles
    if(unit == "K"){//Kilometers
      dist = dist * 1.609344;
    }else if (unit == "N") {//nautical miles
      dist = dist * 0.8684;
    }
    return dist;
  }