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。