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<Character, Integer> CHARSMAP;

 static {
  CHARSMAP = new HashMap<Character, Integer>();
  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<String> getGeoHashBase32For9() {
  double leftLat = location.getLat() - minLat;
  double rightLat = location.getLat() + minLat;
  double upLng = location.getLng() - minLng;
  double downLng = location.getLng() + minLng;
  List<String> base32For9 = new ArrayList<String>();
  //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。