The Java implementation calculates the distance between geographical coordinates

Java to calculate the distance between two latitude and longitude points, directly on the code, please refer to the comments for specific explanation

package com.jttx.poi.utils;

import com.jttx.poi.entity.Point;

/**

 * Created by louis on 2014/9/2.

 */

public class GeoUtils {

    /**

     *  Calculate the distance between two longitude and latitude points (in meters) 

     * @param lng1   longitude 

     * @param lat1   latitude 

     * @param lng2

     * @param lat2

     * @return

     */

    public static double getDistance(double lng1,double lat1,double lng2,double lat2){

        double radLat1 = Math.toRadians(lat1);

        double radLat2 = Math.toRadians(lat2);

        double a = radLat1 - radLat2;

        double b = Math.toRadians(lng1) - Math.toRadians(lng2);

        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1)

                * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));

        s = s * 6378137.0;//Take the length radius of the earth in WGS84 standard reference ellipsoid (unit :m)

        s = Math.round(s * 10000) / 10000;

        return s;

    }

    /**

     *  To calculate TP value 

     * @param curPoint       The current point 

     * @param relatedPoint   Offset point 

     * @param isGeography    Is it a geographic coordinate  false for 2d coordinates 

     * @return              tp value 

     */

    public static double getDirAngle(Point curPoint,Point relatedPoint,boolean isGeography){

        double result = 0;

        if(isGeography){

            double y2 = Math.toRadians(relatedPoint.getLat());

            double y1 = Math.toRadians(curPoint.getLat());

            double alpha = Math.atan2(relatedPoint.getLat() - curPoint.getLat(), (relatedPoint.getLng() - curPoint.getLng()) * Math.cos((y2 - y1) / 2));//The latitude times the cosine of y2 minus y1/2 is less than br over >
            double delta =alpha<0?(2*Math.PI+alpha):alpha;

            result = Math.toDegrees(delta);

        }else {

            double alpha = Math.atan2(relatedPoint.getLat() - curPoint.getLat(), relatedPoint.getLng() - curPoint.getLng());

            double delta=alpha<0?(2*Math.PI+alpha):alpha;

            result = Math.toDegrees(delta);

        }

        return result;

    }

    public static void main(String[] args) {

        System.out.println(getDistance(121.446014,31.215937,121.446028464238,31.2158502442799  ));

    }

}

That's all for this article, I hope you enjoy it.