根据经纬度查询附近的点

大致思想：根据给定经纬度(lat,lng)求出其左上角(left_top),右上角(right_top),左下角(left_bottom)，右下角(right_bottom)的四个位置。所有在这个区域的范围都在该点附近。
参照：http://blog.charlee.li/location-search/

package com.show.common.util;



public class Location {

    private double latitude;

    private double longitude;



    public Location(double latitude, double longitude) {

        this.latitude = latitude;

        this.longitude = longitude;

    }



    public double getLatitude() {

        return latitude;

    }



    public void setLatitude(double latitude) {

        this.latitude = latitude;

    }



    public double getLongitude() {

        return longitude;

    }



    public void setLongitude(double longitude) {

        this.longitude = longitude;

    }



}

package com.show.common.util;



public class LatitudeLontitudeUtil {



    // http://blog.charlee.li/location-search/



    /** 地球半径 */

    private static final double EARTH_RADIUS = 6371000;

    /** 范围距离 */

    private double distance;

    /** 左上角 */

    private Location left_top = null;

    /** 右上角 */

    private Location right_top = null;

    /** 左下角 */

    private Location left_bottom = null;

    /** 右下角 */

    private Location right_bottom = null;



    private LatitudeLontitudeUtil(double distance) {

        this.distance = distance;

    }



    private void getRectangle4Point(double lat, double lng) {



        // float dlng = 2 * asin(sin(distance / (2 * EARTH_RADIUS)) / cos(lat));

        // float dlng = degrees(dlng) // 弧度转换成角度

        double dlng = 2 * Math.asin(Math.sin(distance / (2 * EARTH_RADIUS))

                / Math.cos(lat));

        dlng = Math.toDegrees(dlng);



        // dlat = distance / EARTH_RADIUS

        // dlng = degrees(dlat) # 弧度转换成角度

        double dlat = distance / EARTH_RADIUS;

        dlat = Math.toDegrees(dlat); // # 弧度转换成角度



        // left-top : (lat + dlat, lng - dlng)

        // right-top : (lat + dlat, lng + dlng)

        // left-bottom : (lat - dlat, lng - dlng)

        // right-bottom: (lat - dlat, lng + dlng)

        left_top = new Location(lat + dlat, lng - dlng);

        right_top = new Location(lat + dlat, lng + dlng);

        left_bottom = new Location(lat - dlat, lng - dlng);

        right_bottom = new Location(lat - dlat, lng + dlng);



    }



    public static double hav(double theta) {

        double s = Math.sin(theta / 2);

        return s * s;

    }



    public static double getDistance(double lat0, double lng0, double lat1,

            double lng1) {

        // from math import sin, asin, cos, radians, fabs, sqrt



        // def hav(theta):

        // s = sin(theta / 2)

        // return s * s



        // def get_distance_hav(lat0, lng0, lat1, lng1):

        // "用haversine公式计算球面两点间的距离。"

        // # 经纬度转换成弧度

        // lat0 = radians(lat0)

        // lat1 = radians(lat1)

        // lng0 = radians(lng0)

        // lng1 = radians(lng1)



        // dlng = fabs(lng0 - lng1)

        // dlat = fabs(lat0 - lat1)

        // h = hav(dlat) + cos(lat0) * cos(lat1) * hav(dlng)

        // distance = 2 * EARTH_RADIUS * asin(sqrt(h))



        // return distance

        lat0 = Math.toRadians(lat0);

        lat1 = Math.toRadians(lat1);

        lng0 = Math.toRadians(lng0);

        lng1 = Math.toRadians(lng1);



        double dlng = Math.abs(lng0 - lng1);

        double dlat = Math.abs(lat0 - lat1);

        double h = hav(dlat) + Math.cos(lat0) * Math.cos(lat1) * hav(dlng);

        double distance = 2 * EARTH_RADIUS * Math.asin(Math.sqrt(h));



        return distance;

    }



    public static Location[] getRectangle4Point(double lat, double lng,

            double distance) {

        LatitudeLontitudeUtil llu = new LatitudeLontitudeUtil(distance);

        llu.getRectangle4Point(lat, lng);

        Location[] locations = new Location[4];

        locations[0] = llu.left_top;

        locations[1] = llu.right_top;

        locations[2] = llu.left_bottom;

        locations[3] = llu.right_bottom;

        return locations;

    }



    public static void main(String[] args) {

        double lat = 30.500;

        double lng = 120.500;

        double distance = 500d;

        Location[] locations = LatitudeLontitudeUtil.getRectangle4Point(lat,

                lng, distance);

        String sql = "SELECT * FROM place WHERE lat > "

                + locations[2].getLatitude() + " AND lat < "

                + locations[0].getLatitude() + " AND lng > "

                + locations[0].getLongitude() + " AND lng < "

                + locations[1].getLongitude();

        System.out.println(sql);



        double lat1 = 30.495503391970406;

        double lng1 = 120.49261708577215;

        double d = LatitudeLontitudeUtil.getDistance(lat, lng, lat1, lng1);

        System.out.println(d);

    }

}

 

文章出自：http://0414.iteye.com/blog/2039199