package com.dsh.account.util;


/**
 * 经纬度工具类
 */

public class LonlatUtils {

    public static final double R = 6371; // Earth radius in kilometers

    /**
     * 计算两个经纬度之间的直线距离
     *
     * @param lat1 经度1
     * @param lon1 纬度1
     * @param lat2 经度2
     * @param lon2 纬度2
     * @return 两者距离
     */
    public static double distance(double lat1, double lon1, double lat2, double lon2) {
        double dLat = Math.toRadians(lat2 - lat1);
        double dLon = Math.toRadians(lon2 - lon1);
        double a = Math.sin(dLat / 2) * Math.sin(dLat / 2) +
                Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) *
                        Math.sin(dLon / 2) * Math.sin(dLon / 2);
        double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
        double distance = R * c;
        return distance;
    }


}