distance in Radian - Android java.lang

Android examples for java.lang:Math Trigonometric Function

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Description

distance in Radian

Demo Code


//package com.java2s;

public class Main {
    public static double distance(double lat1, double lon1, double lat2,
            double lon2) {

        if ((lat1 == lat2) && (lon1 == lon2)) {
            return 0;
        } else/*  w  w w . j av  a  2 s . c  o m*/
            return distance(lat1, lon1, lat2, lon2, 'K');
    }

    public static double distance(double lat1, double lon1, double lat2,
            double lon2, char 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;
        if (unit == 'K') {
            dist = dist * 1.609344;
        } else if (unit == 'N') {
            dist = dist * 0.8684;
        }
        return (dist);
    }

    private static double deg2rad(double deg) {
        return (deg * Math.PI / 180.0);
    }

    private static double rad2deg(double rad) {
        return (rad * 180.0 / Math.PI);
    }
}

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