geohash用java实现_Java将GeoHash转化为对应的经纬度坐标实例代码
本文实例介绍了JAVA实现将GeoHash转化为对应的经纬度坐标的详细代码，分享给大家供大家参考，具体内容如下
package com.lulei.geo;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import com.lulei.geo.bean.LocationBean;
import com.lulei.util.JsonUtil;
public class GeoHash {
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;//每个经度的单位大小
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'};
private static HashMap CHARSMAP;
static {
CHARSMAP = new HashMap();
for (int i = 0; i < CHARS.length; i++) {
CHARSMAP.put(CHARS[i], i);
}
}
public GeoHash(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 i
* @return
* @Author:lulei
* @Description: 将数字转化为二进制字符串
*/
private String getBase32BinaryString(int i) {
if (i < 0 || i > 31) {
return null;
}
String str = Integer.toBinaryString(i + 32);
return str.substring(1);
}
/**
* @param geoHash
* @return
* @Author:lulei
* @Description: 将geoHash转化为二进制字符串
*/
private String getGeoHashBinaryString(String geoHash) {
if (geoHash == null || "".equals(geoHash)) {
return null;
}
StringBuffer sb = new StringBuffer();
for (int i = 0; i < geoHash.length(); i++) {
char c = geoHash.charAt(i);
if (CHARSMAP.containsKey(c)) {
String cStr = getBase32BinaryString(CHARSMAP.get(c));
if (cStr != null) {
sb.append(cStr);
}
}
}
return sb.toString();
}
/**
* @param geoHash
* @return
* @Author:lulei
* @Description: 返回geoHash 对应的坐标
*/
public LocationBean getLocation(String geoHash) {
String geoHashBinaryStr = getGeoHashBinaryString(geoHash);
if (geoHashBinaryStr == null) {
return null;
}
StringBuffer lat = new StringBuffer();
StringBuffer lng = new StringBuffer();
for (int i = 0; i < geoHashBinaryStr.length(); i++) {
if (i % 2 != 0) {
lat.append(geoHashBinaryStr.charAt(i));
} else {
lng.append(geoHashBinaryStr.charAt(i));
}
}
double latValue = getGeoHashMid(lat.toString(), LocationBean.MINLAT, LocationBean.MAXLAT);
double lngValue = getGeoHashMid(lng.toString(), LocationBean.MINLNG, LocationBean.MAXLNG);
LocationBean location = new LocationBean(latValue, lngValue);
location.setGeoHash(geoHash);
return location;
}
/**
* @param binaryStr
* @param min
* @param max
* @return
* @Author:lulei
* @Description: 返回二进制对应的中间值
*/
private double getGeoHashMid(String binaryStr, double min, double max) {
if (binaryStr == null || binaryStr.length() < 1) {
return (min + max) / 2.0;
}
if (binaryStr.charAt(0) == '1') {
return getGeoHashMid(binaryStr.substring(1), (min + max) / 2.0, max);
} else {
return getGeoHashMid(binaryStr.substring(1), min, (min + max) / 2.0);
}
}
/**
* @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;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
GeoHash g = new GeoHash(40.221227, 116.24875);
String geoHash = g.getGeoHashBase32();
System.out.println(geoHash);
LocationBean bean = g.getLocation(geoHash);
System.out.println(JsonUtil.parseJson(bean));
System.out.println(new GeoHash(bean.getLat(), bean.getLng()).getGeoHashBase32());
System.out.println(DistanceUtil.getDistance(bean.getLat(), bean.getLng(), bean.getLat() - g.minLat, bean.getLng() - g.minLng));
}
}
以上就是本文的详细内容，希望对大家的学习有所帮助。
时间： 2016-01-22