根據已知經緯度和指定的範圍求出最大及最小的經緯度

public class LatLonUtil {

    private static final double PI = 3.14159265;
    private static final double EARTH_RADIUS = 6378137;
    private static final double RAD = Math.PI / 180.0;

    //@see http://snipperize.todayclose.com/snippet/php/SQL-Query-to-Find-All-Retailers-Within-a-Given-Radius-of-a-Latitude-and-Longitude--65095/
    //The circumference of the earth is 24,901 miles.
    //24,901/360 = 69.17 miles / degree
    /**
     * @param raidus 單位米
     * return minLat,minLng,maxLat,maxLng
     */
    public static double[] getAround(double lat,double lon,int raidus){

        Double latitude = lat;
        Double longitude = lon;

        Double degree = (24901*1609)/360.0;
        double raidusMile = raidus;

        Double dpmLat = 1/degree;
        Double radiusLat = dpmLat*raidusMile;
        Double minLat = latitude - radiusLat;
        Double maxLat = latitude + radiusLat;

        Double mpdLng = degree*Math.cos(latitude * (PI/180));
        Double dpmLng = 1 / mpdLng;
        Double radiusLng = dpmLng*raidusMile;
        Double minLng = longitude - radiusLng;
        Double maxLng = longitude + radiusLng;
        //System.out.println("["+minLat+","+minLng+","+maxLat+","+maxLng+"]");
        return new double[]{minLat,minLng,maxLat,maxLng};
    }

    /**
     * 根據兩點間經緯度座標（double值），計算兩點間距離，單位爲米
     * @param lng1
     * @param lat1
     * @param lng2
     * @param lat2
     * @return
     */
    public static double getDistance(double lng1, double lat1, double lng2, double lat2)
    {
       double radLat1 = lat1*RAD;
       double radLat2 = lat2*RAD;
       double a = radLat1 - radLat2;
       double b = (lng1 - lng2)*RAD;
       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 * EARTH_RADIUS;
       s = Math.round(s * 10000) / 10000;
       return s;
    }

    public static void main(String[] args){
        Double lat1 = 34.264648;
        Double lon1 = 108.952736;

        int radius = 1000;
        //[34.25566276027792,108.94186385411045,34.27363323972208,108.96360814588955]
        getAround(lat1,lon1,radius);

        //911717.0   34.264648,108.952736,39.904549,116.407288
        double dis = getDistance(108.952736,34.264648,116.407288,39.904549);
        System.out.println(dis);
    }
}