This article introduces the detailed code of JAVA to convert GeoHash into corresponding latitude and longitude coordinates. It is shared with you for your reference. The specific content is as follows
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; //Latitude and longitude are converted into geohash length private int latLength = 20; //Latitude and longitude are converted into binary length private int lngLength = 20; //Latitude and longitude are converted into binary length private double minLat; //Unit size of each latitude private double minLng; //Unit size of each latitude 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: Set the minimum unit of latitude and longitude*/ 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: Find the nine coordinate points and surrounding points */ 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>(); //The three Strings on the left from top to bottom 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); } //The 3 Strings from top to bottom in the middle 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); } //3 Strings from top to bottom on the right side 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: Set the latitude and longitude to geohash length*/ 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: Get the base32 string of latitude and longitude*/ public String getGeoHashBase32() { return getGeoHashBase32(location.getLat(), location.getLng()); } /** * @param lat * @param lng * @return * @Author:lulei * @Description: Get the base32 string of latitude and longitude*/ 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: Convert five-bit binary to 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: Convert numbers to binary string */ 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: Convert geoHash to binary string */ 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: Return the coordinates corresponding to geoHash*/ 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: Return the intermediate value corresponding to the binary*/ 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: Get the geo binary string of coordinates*/ 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: Merge latitude and longitude binary*/ 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: Convert numbers into geohash binary string*/ 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(), bean.getLat() - g.minLat, bean.getLng() - g.minLng)); } }The above is the detailed content of this article, I hope it will be helpful to everyone's learning.