Query nearby points by longitude and latitude

General idea: Based on the given latitude and longitude (Lat, LNG), find the four positions in the upper left corner (left_top), upper right corner (right_top), lower left corner (left_bottom), and lower right corner (right_bottom. All the ranges in this region are near this point.
Reference: 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//** /*/Private Static final double earth_radius = 6371000;/** range distance */private double distance; /** upper left corner */private location left_top = NULL;/** upper right corner */private location right_top = NULL;/** lower left corner */private location left_bottom = NULL; /** bottom right corner */private location right_bottom = NULL; PRI Vate 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) // converts radians to degrees double dlng = 2 * Math. asin (math. sin (distance/(2 * earth_radius)/math. cos (LAT); dlng = math. todegrees (dlng); // dlat = distance/earth_radius // DL Ng = degrees (dlat) # convert radians to degrees double dlat = distance/earth_radius; dlat = math. todegrees (dlat); // converts radians to degrees // 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 (L At-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, ln G0, LAT1, lng1): // "The haversine formula is used to calculate the distance between two points of the sphere. "// # Converts longitude and latitude to radians // 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]. getlonglinks () + "and LNG <" + locations [1]. getlongpolling (); system. out. println (SQL); double LAT1 = 30.495503391970406; double lng1 = 120.49261708577215; double D = latitudelontitudeutil. getdistance (Lat, LNG, LAT1, lng1); system. out. println (d );}}

 

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