比较两个经纬度之间的直线距离
public static double distanceByLongNLat(double long1, double lat1, double long2, double lat2) { double a, b, R; R = 6378137;//地球半径 lat1 = lat1 * Math.PI / 180.0; lat2 = lat2 * Math.PI / 180.0; a = lat1 - lat2; b = (long1 - long2) * Math.PI / 180.0; double d; double sa2, sb2; sa2 = Math.sin(a / 2.0); sb2 = Math.sin(b / 2.0); d = 2 * R * Math.asin(Math.sqrt(sa2 * sa2 + Math.cos(lat1) * Math.cos(lat2) * sb2 * sb2)); return d; }