java geohash_GeoHash(Java实现)

package com.koubei.collect_script.demo;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

/**

* @author kelin.ll

* @date on 2018/6/13

*/

public class GeoHashDemo {

private LocationBean location;

/**

* 1 2500km;2 630km;3 78km;4 30km

* 5 2.4km; 6 610m; 7 76m; 8 19m

*/

private int hashLength = 8; //经纬度转化为geohash长度

private int latLength = 20; //纬度转化为二进制长度

private int lngLength = 20; //经度转化为二进制长度

private double minLat;//每格纬度的单位大小

private double minLng;//每个经度的倒下

private static final char[] CHARS = {'0', '1', '2', '3', '4', '5', '6', '7',

'8', '9', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n',

'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};

public GeoHashDemo(double lat, double lng) {

location = new LocationBean(lat, lng);

setMinLatLng();

}

public int gethashLength() {

return hashLength;

}

/**

* @Author:lulei

* @Description: 设置经纬度的最小单位

*/

private void setMinLatLng() {

minLat = LocationBean.MAXLAT - LocationBean.MINLAT;

for (int i = 0; i < latLength; i++) {

minLat /= 2.0;

}

minLng = LocationBean.MAXLNG - LocationBean.MINLNG;

for (int i = 0; i < lngLength; i++) {

minLng /= 2.0;

}

}

/**

* @return

* @Author:lulei

* @Description: 求所在坐标点及周围点组成的九个

*/

public List getGeoHashBase32For9() {

double leftLat = location.getLat() - minLat;

double rightLat = location.getLat() + minLat;

double upLng = location.getLng() - minLng;

double downLng = location.getLng() + minLng;

List base32For9 = new ArrayList();

//左侧从上到下 3个

String leftUp = getGeoHashBase32(leftLat, upLng);

if (!(leftUp == null || "".equals(leftUp))) {

base32For9.add(leftUp);

}

String leftMid = getGeoHashBase32(leftLat, location.getLng());

if (!(leftMid == null || "".equals(leftMid))) {

base32For9.add(leftMid);

}

String leftDown = getGeoHashBase32(leftLat, downLng);

if (!(leftDown == null || "".equals(leftDown))) {

base32For9.add(leftDown);

}

//中间从上到下 3个

String midUp = getGeoHashBase32(location.getLat(), upLng);

if (!(midUp == null || "".equals(midUp))) {

base32For9.add(midUp);

}

String midMid = getGeoHashBase32(location.getLat(), location.getLng());

if (!(midMid == null || "".equals(midMid))) {

base32For9.add(midMid);

}

String midDown = getGeoHashBase32(location.getLat(), downLng);

if (!(midDown == null || "".equals(midDown))) {

base32For9.add(midDown);

}

//右侧从上到下 3个

String rightUp = getGeoHashBase32(rightLat, upLng);

if (!(rightUp == null || "".equals(rightUp))) {

base32For9.add(rightUp);

}

String rightMid = getGeoHashBase32(rightLat, location.getLng());

if (!(rightMid == null || "".equals(rightMid))) {

base32For9.add(rightMid);

}

String rightDown = getGeoHashBase32(rightLat, downLng);

if (!(rightDown == null || "".equals(rightDown))) {

base32For9.add(rightDown);

}

return base32For9;

}

/**

* @param length

* @return

* @Author:lulei

* @Description: 设置经纬度转化为geohash长度

*/

public boolean sethashLength(int length) {

if (length < 1) {

return false;

}

hashLength = length;

latLength = (length * 5) / 2;

if (length % 2 == 0) {

lngLength = latLength;

} else {

lngLength = latLength + 1;

}

setMinLatLng();

return true;

}

/**

* @return

* @Author:lulei

* @Description: 获取经纬度的base32字符串

*/

public String getGeoHashBase32() {

return getGeoHashBase32(location.getLat(), location.getLng());

}

/**

* @param lat

* @param lng

* @return

* @Author:lulei

* @Description: 获取经纬度的base32字符串

*/

private String getGeoHashBase32(double lat, double lng) {

boolean[] bools = getGeoBinary(lat, lng);

if (bools == null) {

return null;

}

StringBuffer sb = new StringBuffer();

for (int i = 0; i < bools.length; i = i + 5) {

boolean[] base32 = new boolean[5];

for (int j = 0; j < 5; j++) {

base32[j] = bools[i + j];

}

char cha = getBase32Char(base32);

if (' ' == cha) {

return null;

}

sb.append(cha);

}

return sb.toString();

}

/**

* @param base32

* @return

* @Author:lulei

* @Description: 将五位二进制转化为base32

*/

private char getBase32Char(boolean[] base32) {

if (base32 == null || base32.length != 5) {

return ' ';

}

int num = 0;

for (boolean bool : base32) {

num <<= 1;

if (bool) {

num += 1;

}

}

return CHARS[num % CHARS.length];

}

/**

* @param lat

* @param lng

* @return

* @Author:lulei

* @Description: 获取坐标的geo二进制字符串

*/

private boolean[] getGeoBinary(double lat, double lng) {

boolean[] latArray = getHashArray(lat, LocationBean.MINLAT, LocationBean.MAXLAT, latLength);

boolean[] lngArray = getHashArray(lng, LocationBean.MINLNG, LocationBean.MAXLNG, lngLength);

return merge(latArray, lngArray);

}

/**

* @param latArray

* @param lngArray

* @return

* @Author:lulei

* @Description: 合并经纬度二进制

*/

private boolean[] merge(boolean[] latArray, boolean[] lngArray) {

if (latArray == null || lngArray == null) {

return null;

}

boolean[] result = new boolean[lngArray.length + latArray.length];

Arrays.fill(result, false);

for (int i = 0; i < lngArray.length; i++) {

result[2 * i] = lngArray[i];

}

for (int i = 0; i < latArray.length; i++) {

result[2 * i + 1] = latArray[i];

}

return result;

}

/**

* @param value

* @param min

* @param max

* @return

* @Author:lulei

* @Description: 将数字转化为geohash二进制字符串

*/

private boolean[] getHashArray(double value, double min, double max, int length) {

if (value < min || value > max) {

return null;

}

if (length < 1) {

return null;

}

boolean[] result = new boolean[length];

for (int i = 0; i < length; i++) {

double mid = (min + max) / 2.0;

if (value > mid) {

result[i] = true;

min = mid;

} else {

result[i] = false;

max = mid;

}

}

return result;

}

class LocationBean {

public static final double MINLAT = -90;

public static final double MAXLAT = 90;

public static final double MINLNG = -180;

public static final double MAXLNG = 180;

private double lat;//纬度[-90,90]

private double lng;//经度[-180,180]

public LocationBean(double lat, double lng) {

this.lat = lat;

this.lng = lng;

}

public double getLat() {

return lat;

}

public void setLat(double lat) {

this.lat = lat;

}

public double getLng() {

return lng;

}

public void setLng(double lng) {

this.lng = lng;

}

}

public static void main(String[] args) {

// TODO Auto-generated method stub

GeoHashDemo g = new GeoHashDemo(40.222012, 116.248283);

g.sethashLength(12);

System.out.println("当前坐标："+g.getGeoHashBase32());

//for (String str:

// g.getGeoHashBase32For9()) {

// System.out.println(str);

//}

}

}